"Much like a warrant for a home or business premises, why should it not be enforceable for digital things too?"
In most (democratic) countries you do not have to cooperate with the police if they have a warrant. So they are allowed to search your house, they are allowed to break your lock/door, but you are not obligated to give them the key to your house.
It's already the same with digital things: The police can get a warrant and is then allowed to try to crack my password. But I'm not obligated to give them the key.