OTOH, I'd never try that with my keyboard, which can only do USB or Bluetooth. BT has become very good, but for an input device, it's not quite as good as cabled.

For head-/earphones, the difference is night and day. My fondleslabs have headphone jacks, but if I had to use an adapter (lightning, USB-C, whatever) to get that jack, it would be even more clear: I'm using the cable for a reason; Bluetooth will never ever suffice in that situation.