My guess is no one is willing to take on the liability. Any new system that introduces bugs or introduces attack vectors from hackers don’t want to be responsible for any lost money and I’m sure banks/insurance don’t want to take on the risk either.
Magnetic tape and clearing houses for the indefinite future!
From my time on Reddit years ago this question came up.
Some cashier’s said they reciprocate the exchange back to the customer. If the customer puts cash on the counter for them to pick up, they’ll put the change on the counter in return.
There also was probably some new training from covid where you didn’t want to touch people directly, so those training materials probably still exist