That would absolutely explain why I've never seen it. In my generation, if I invite people out, I expect to pay the bill. There is no bill splitting. If I'm paying someone, I've probably got cash.
Yeah, I even have a landline. I did mention I'm old. ;-)
Square, meanwhile, is offering both business and peer-to-peer options.
It might be a generational thing, but it does seem like Venmo has cornered the p2p market.