Venmo - which in my experience is ubiquitous - is for sending money to and from friends and acquaintances (often for things like dinners, drinks, tickets etc),

Venmo - which in my experience is ubiquitous - is for sending money to and from friends and acquaintances (often for things like dinners, drinks, tickets etc), not for e-commerce (although my landlord takes venmo). Using PayPal would definitely be an 'old guy' tell.