Pennies playing hard to get

My kids are fine without cash—they use debit & credit cards, as well as D using some app to transfer funds—Venmo. S also wires money. It works well for them. I’m fine with cash, debit & CCards. So far, haven’t wired funds nor apps for funds. My kids are in NYC & LA, both large cities. D has been paying rent via Venmo for ages.