Considering both senior politicians in Lithuania and Luxembourg have raised formal concerns about Revolut's bid for a bank licence, specifically because of the CEO's alleged Kremlin ties, I'm willing to assume there's some substance to that concern.
We use Revolut around the office to split bills for lunches, etc, but I wouldn't keep more than few bucks in there.
They have a banking license from Lithuania (but customers are not switched to it) which might be revoked by Lithuania and they are trying for another license in Ireland.
Thanks to comment below - edited this make more sense.
[1] https://www.theguardian.com/money/2018/dec/22/lithuania-icel...
I don't use Venmo myself - I'm at a point where I'd rather just pick up the check that try to split it (using any method). And let me friends pick up the next meal.
They're only covered against bankruptcy though - if someone steals your phone and drains your account, you're SOL.