I don't use this app and this article kind of explains why. If I go to dinner with friends, or anything, I'd rather pick up the check than worry about splitting it. The next time, they'll pickup the tab, and so forth. That's what friends do. I don't know if I'd want to go out with someone who is going to bill me for it later, or wants to use an app to split things up. For me it just makes things superficial, awkward,…
I think it's simple common courtesy that the person extending the invite picks up the check.