whenever you want to purchase with fiat (no matter what method of fiat deposit you choose) you will have to send your documents including picture,... to the place you are doing the purchase from. that is not just about credit cards. some places don't even allow you to buy anything if you don't verify your account first.
You're right, however some places require you to hold your ID and CC by your face and send them a selfie. Others require you simply send a picture of your ID. The second is my preferred way, I hate selfies in the first place and especially sending them to some random exchange is even worse.