What benefit would it serve?

It's of no benefit to users who don't notice their question was closed in the first place. If they weren't interested then, they're not likely to be interested now.

If they are interested in the fate of their question then we assume that they noticed the closure and took steps to fix the question. At this point it enters the re-open queue. If it gets re-opened then there's nothing more for the user to do. The question is now deemed good enough and is ready to accept answers.

If it's still not good enough to re-open they'll need to do some more work on it. Therefore they'll have to stick around monitoring it until it gets reopened.

Even if they edit the question and then forget about it, they'll get a notification if the question is answered - which will coincidentally notify them that the question was re-opened. So you see the system already does what you're suggesting (sort of).

This answer is now out of date because a notification has been implemented

I'm not sure what benefit this would serve, but it might help in some cases.

It's of no benefit to users who don't notice their question was closed in the first place. If they weren't interested then, they're not likely to be interested now.

If they are interested in the fate of their question then we assume that they noticed the closure and took steps to fix the question. At this point it enters the re-open queue. If it gets re-opened then there's nothing more for the user to do. The question is now deemed good enough and is ready to accept answers.

If it's still not good enough to re-open they'll need to do some more work on it. Therefore they'll have to stick around monitoring it until it gets reopened.

Even if they edit the question and then forget about it, they'll get a notification if the question is answered - which will coincidentally notify them that the question was re-opened. So you see the system already does what you're suggesting (sort of).