Because it's a service that also offers something related to bitcoin...not really sure what but since you mentioned revolut I assume you're buying CFD not BTC, right?
Well, they get a bit more free advertising, we get a little more hype, nobody will use it to covert fake BTC to money since, well you have your usual card for this, and we'll wait till the next service to pop-up.
Because there is none!
And it's not just the bank, in order for those cards to function all over the place they will have to be issued under either Visa or Mastercard and if one of those thinks the bank is not really complying with their terms they will shut them all down as they did with WaveCrest.
Keep dreaming...