Dear Revolut. This is urgent and necessary. Great that you offer your customers to buy Bitcoin et al, but by disallowing or not providing an option to transact out, you are putting your customers funds at risk. You are making yourself a target. Have recent hacks taught us nothing? This is not optional. This is required part of the service.
Your keys - your bitcoin. Not your keys - not your bitcoin.
Right now, if I understand your terms of service correctly, I am buying bitcoin for you with my own money. Until this is fixed, I am staying away from trading cryptocurrencies with Revolut.