Even if the person you want to transact with doesn't have it, it will handle that on their side. Really good UX because there practically is none.
Is there any reason you prefer Square Cash?
I haven't seen Square Cash 2.0, but I don't really see myself or my friends branching out from the dead simple email usage.
1. People have usually heard of those little smartphone card swiper things.
2. It doesn't require any account setup or installation.
3. It works through email, which is already what we were using to communicate on craigslist.
Venmo doesn't post the amount to facebook on the payee's wall, but posts the short text description that the payer who pays the payee writes in venmo when making the payment.
IMO this is TMI and a 'not-so-good' friend of yours could see you receiving a lot of payments on venmo that appear on your facebook wall and then decide to rob you.
What's the potential for abuse?
Also look how far the politically connected go to avoid taking cash from the "wrong donors" (e.g.: NRA contributing to a anti-gun activist).
Person A wants to ruin person B's day. So person A plants rumors that person B has been bribed, and gets some random shady person to send a reasonably large amount to person B.