There are companies that are accepted with just an idea and companies with six figure revenues that are rejected. There are founders with bad ideas that are "funded for the pivot," and founders like Drew Houston who are rejected because their initial idea was bad.
It just seems kind of random.
So for example. If you're a Stanford grad, have already started and exited a company and now are a part-time VC, you can probably get into YC with just an idea. (similar to Standard Treasury).
Alternatively if you've not made a name for yourself yet it's likely YC would look for something already built, with users, and possibly revenue.
This is obviously pure speculation.
(2) Dan and I are part-time angels really, with very small checks given to a very small number of companies. Also, as sama mentioned, we basically stopped investing at all once we got into YC. We still make an investment from time-to-time but mostly in people we know already. We don't have meetings, way too busy on Standard Treasury.
(3) We felt like an underdog when we applied to YC. I think we were underdogs when we applied! We didn't know them and certainly didn't have much of a reputation outside of financial technology (still don't?). We felt very fortunate when we got in. YC was amazing for us and has always been supportive of our mild madness.
We raised the money from friends, neither Dan and I are really financially capable of making investments ourselves. So, we're both privileged in that we've hustled and got people to have faith in us; however, both of us came from humble backgrounds (my mom and dad were a waitress and a postman, respectively) and neither of us have done that well for ourselves...yet.
And my comment wasn't meant to come off as "these are exactly the things Standard Treasury did to get in". It was more of a comparison of the type of founders YC would look for in a product that is still in the initial idea phase. So thanks for clearing that up.
The angel thing is actually interesting to me. You don't think that had any weight on YC's decision to admit you guys? To me it would seem like someone who could clearly support themselves financially enough to be an angel would be an ideal candidate as a founder...but I'm not an investor so I have no idea if these things are good or bad.