You have to be 13 to have FB and other social media accounts too, but somehow everyone in third grade except my kids had them. The reason for the social media accounts is that there is a federal law about disclosures and to avoid having to deal with them, FB (and MySpace, etc) just set the age at 13. Kids just change their birthdates on the set up page. My cousin just turned 15 on Saturday and two FB notices popped up, one saying he was 15, the other saying 22! I think he set up an illegal account a few years before he should have.
Most states require a person to be 18 to be bound by a contract, so credit cards, bank accounts, or even buying property require the person to be 18 or have a parent sign. Otherwise, when the child turns 18 he/she can void all the prior transactions. Venmo and the rest are the same, and don’t want the users to void all the prior transactions and demand their money back when they turn 18.
Around here, Uber and Lyft do not ‘allow’ those under 18 to call for a ride, even if they are using an authorized credit card. They aren’t very good at enforcing it, but that is the official rule. They had a few cases of 13 year olds calling for Ubers at 1 am and going to friends’ homes, to malls, etc. The parents gave the kids a cell phone, credit card access, house keys, but it is Uber’s responsibility to not give them a ride?