Totally makes sense IMHO. Even subscriptions are essentially a simplified/averaged "pay for what you use".

The question is rather whether a single type of subscription license makes sense (e.g. when AI burns through more resources than the average human, should the subscription go up for everybody? - as a human I would be pissed to subsidise heavy AI usage by other users).

E.g. there should probably be special 'AI licenses' similar to how some products have special 'CI licenses'.