But there in lies the problem. Not only do they not know when the attraction will come on line, they may not even know when they will know when the attraction will come back online.
So to put it in an example... Let's assume the attraction goes down at 11am, and you had a FP for 11:30am and are notified at 11am that the attraction is down. The ride system is down, and they can't figure out why.. and they need to get the mechanics involved. They work at it for awhile before they know the root cause. Finally at 6pm, they figured out the problem, and know the ride will reopen at 6:30.
So what happened in your example? You were forced to wait for 7.5hrs before you knew what you could do with your valuable FP+ allocation. You are forced to wait in limbo with this 'valuable' 1 of 3 allocation you have for the day. Complicating that, at what point should the system decide 'if we don't reallocate you now, you will lose out entirely because it can't practically be applied elsewhere and your FP+ will have no value'?? Because it's an unknown time when they will know the answer.. you have a second decision 'when do I punt and just give up on the wait'?
So by offering you the ability to reallocate your FP+ earlier.. you are no longer forced to wait in limbo. This is the customer value in this solution.. it frees up your FP+ to be reused.
Now, maybe the downtime is much shorter.. and you're willing to wait it out to try to reschedule. But you probably don't want that to be the default behavior... because the more people that do that.. the harder it is to fit them back in... the longer the downtime, the more people displaced and the less time to fit them in.
This is why (again) I said earlier.. I wonder if the block is not being able to rebook while the attraction is down, or if they will block rebooking entirely for the same attraction. The latter would be the situation where you want to 'wait it out'... but you don't want 'wait it out' to be the default in alot of scenarios as I outlined above.