That's odd. Literally 95% of my friends are on Venmo, with the only holdouts being the people who refuse to grant account withdrawal permissions to a third party.
I don't like the "bucket" approach or Venmo's emphasis on linking to Facebook, so I don't have an account and use Square Cash or BofA transfers instead. I'm the exception though, I'd agree that the vast majority of my friends use it.
That was me up until a few months ago. A combination of a good track record and not wanting to be "that guy" caused me to switch. Don't make me regret it Venmo!