I don't like USB-C because they all look the same on the outside, but they're not all the same on the inside. Especially my cheap consumer electronics. Sometimes they will charge, sometimes they won't charge, but all the cables look the same, and you don't tend to know in advance.
This is an acceptable failure mode. I'd be nice if there was a standardized LED flash or color that you could get so if your relative said something isn't working, you could ask, "Is it flashing three times?" or whatever. The alternative is barrel connectors. If you plug in the wrong one, there's a decent chance that it a) won't work, or b) never work again.
Or you just borrow their USB-C adapter and don't have any worries.