Why bother stealing it? All that's going to do is attract attention and get your stolen plate flagged/revoked. Copying someone else's plate achieves the same goal without the unnecessary attention.
The more advanced A.I systems (talking specifically about number plate recognition systems here) are coded to detect 'time travel' vehicles and flag up simultaneous ANPR (Automated Number Plate Recognition) activations to detect (and prevent) number plate cloning to avoid tax, road worthiness checks etc so they only work as long as the ‘donor’ vehicle doesn’t go past an ANPR camera so in terms of time gained it works out as roughly about the same because people notice either that their plates are missing or a simultaneous ping occurs and they see blue lights in their mirror. If you were taking it from a preplanned use of a false number plate situation - in those sorts of circumstances a hire car and forged documentation is the method du jour.