While I'm financially not doing so bad, I grew up poor. When I was college age going out with friends was complicated- if we all handled our own bills it was one thing, but when I'm not drinking and only eating cheap food to save money splitting the check would literally mean I'm subsidizing other people friends and could be the difference between being able to afford to go out or not.
Apps like this level the playing field and make it a lot easier for people of different incomes to socialize together with less awkwardness.