sensitive documents for withdrawal

Honestly, I'm not sure how it is with covering numbers on your driving license. Covering some number on a credit card is allowed, that's for sure. The picture of you holding your license (or any document) is quite a common request from a casino to be honest.

This could be considered as a higher level of verification and it's usually used when the casino is suspicious about you and your account. It could be anything - another player having the same name as you, someone with the same IP address or they simply don't like the pictures you sent before so they decided to ask for a picture of you holding the documents.