You can not use the headset when charging, because the current flow is relatively large at this time, it is likely to burn out, and the basic version, so it can not be used. Only when the headset is fully charged can it be unplugged, and then it can be connected to the phone. In this way, the signal is stable, and there is no electric shock, and the sound quality can be better heard when using.
Of course you can. One company has developed a unique accessory for the AirPods Pro that allows users to charge their devices while using the headphones.
airpods listen while charging, which means that the earphones are taken out to use, not to charge the earphones, but to charge the box separately. Don't I make it clear enough, haha, that I wear headphones while listening to music, the box is also charged separately.