Kids *are* forced to use cashless these days and have been for many years.
On the plus side, it means the money gets spent on what the parents dished it out for, and gets spent by the child it was given to. On the minus side, kids are taught from a young age that biometrics are both secure enough for financial purposes *and* something that you should just hand over to anyone who asks.
Regarding cash, I have cash in my wallet that pre-dates Covid and I suspect I'd get accusatory looks if I tried to use it, so "yes" to that one.