Maven, in my case, both my parents knew they had Native ancestry and told me so long ago. In fact, one of my first attempts at genealogy was trying to contact the Mississippi Choctaw tribal office in hopes they had info on my maternal great-great-grandmother. They told me their records were sketchy in general and they weren't able to help. It wasn't until this year that evidence of Choctaw on that line showed up in Ancestry Hints on my gg-grandmother's half-brother's Dawes application. So for me, I've just always felt the pull to learn more about my ancestors in general and my Native ancestors in particular.
I'm really fortunate because I have most lines on both sides of my tree at least 6 generations or more and some of my Native ancestry is well documented, moreso than others I've had to work harder to find info on. I was also extremely lucky that long before the internet and DNA I had info from my immediate family and several cousins who had already been researching many of my lines and very generously shared their findings (and books some authored) on them. Then I also have some cousins who share Native ancestry with me but their branch was enrolled and mine wasn't. One such case is a 5th cousin who shared Creek ancestors with me is from my ancestral aunt who went to Oklahoma in her 70s. My ancestor who was her sister, however, had died the same year the Dawes roll was implemented and none of my branch left Mississippi and went to Oklahoma. They were all grown, had already raised their families in Mississippi, etc. and stayed put. But the cousin whose line was enrolled shared all the info and family photos, etc. he had. But that also happens to be one of our better documented lines with Congressional records, being mentioned in the writing of Benjamin Hawkins, etc. In any case, I've had a number of such cases as that that have greatly helped me along in my quest to know more about all the lines I come from. Some of my cousins are the 2nd or 3rd generation in their family to carry the torch of family genealogist, which wasn't the case in my immediate family. So for me and those I've worked with, it has been a collaborative project much like working on a huge family jigsaw puzzle and we just enjoy the process of finding new pieces of that puzzle not just for ourselves but for others in the family branches and generations to come. It's just that the internet, collaborative research groups, and DNA testing have all been game-changers for everyone.
All that said, I respectuflly disagree about only Y-DNA nad mtDNA being applicable to placing someone in a lineage. You pointed out the limitations of those two, with which I agree. I had a brick wall on my mtDNA line and thought / hoped mtDNA testing would help me have a breakthrough. It didn't, because I would show matches who could be a close cousin or something like a 23rd cousin and it would still be an mtDNA match and pretty much useless in my research.
And I have found using Y-DNA studies equally useless because people join one of the surname groups and list who they believe their ancestor is, causing their Y-DNA haplogroup to get attached to that person even if they have their tree wrong. That's how we also end up with male lines on Geni showing 2-3 conflicting Y-DNA haplogroups attached to them. The connections are only as correct as the info input by the various individuals. If they aren't biologically who they believe they are, error. If they were adopted and don't know it, error. And these things do happen and it throws everything off for everyone else trying to depend on the Y-DNA surname groups to confirm their lines.
On the other hand, triangulating atDNA can be useful in confirming where cousins share a line. And sites like Ancestry gives us ThruLines matches that are 'usually' correct, but not always and still require double-checking the tree connections, in my opinion. Even Geni 'confirms' atDNA matches to the 7th generation, pulling the info from FTDNA. Gedmatch validates matches to an estimated 7.7 generations but you still have to do the tree work to find 'how' you connect with the matches.
So for me, atDNA is the best DNA tool to combine with tree work. I understand your point and the example of thinking the shared NA DNA is from one branch of a tree but was actually from another. I'm sure that can and does happen. In my own work, however, I think it's different. For example, my Creek line is so well-documented and there are so many surnames on the decendant branches that are very well-known to be from that line. So when they show up in ThruLines, for example, showing the connection to our already known common ancestors on that line, if we share Native DNA, I am confident we share it from our shared Creek ancestry.
So I think it depends on, as you pointed out, how far back the tree(s) are documented back in time, how well-known the lines are in general, etc. I get Native DNA matches on a regular basis where I have no idea how I'm related to the person or who we got the shared Native DNA from. So I'm not saying that in every case I know. I wish I did! My DNA Consultants results show I match Ojibewe and Sioux groups from Minnesota. I have no idea who / how. However, earlier this year I was contacted by a 5th-great-granddaughter of Sioux Chief Sitting Bull's brother Standing Bull who found me among her Gedmatch matches and looked me up on Ancestry. We are a DNA match, we used the Gedmatch chromosome paint tool to validate we share Native DNA, her ancestors are enrolled Native Americans from Minnesota...and we have no idea how we're related. But it did validate my results from DNA Consultants, which was amazing in itself. I'd say about half my Native DNA matches I know who / how we're related either because I know the lines so well or by identifying who our mutual matches are and which line(s)we all connect on. Another 1/4 are with matches who are from enrolled families but I have no clue who/how I connect with them. And the last 1/4 show matching Native DNA but no enrolled family lines and no clues whatsoever as to who / how we're related. On the lines where I know how I'm related to the person but we could have a Native DNA match more than one way...it's always a very close match (on Ancestry, My Heritage, 23andme and/or Gedmatch) and I know which lines we share, and 'usually' the multi-related connection is because on my match's side they have ancestors who are both related to me on a single given connection - like they had ancestors who were were cousins and I know how they connect to each other and to me. My side is easier to identify because I don't have any direct ancestors within recent generations who were married to a close cousin. In my case, any such connection as that is way back like very distant ancestry before America and doesn't apply to any Native American ancestry.
This discussion began about a specific person but she's just one of countless individuals in my family tree. I research them all with equal interest, as well as all of my son's paternal lines, because I do all of this for him. He's the one who got me started on it many years ago because of his personal curiosity about the people he came from. So I'm not sure where you're coming from about 'brownie points' or 'bragging rights'. I don't recall anything in the discussion you joined that indicates that was anyone's purpose in the discussion.