Often times, moves like Link's up-B sits there being useless for a few frames. Those frames are enough to spike him.
The same can be said for anyone that doesn't "snap" to the ledge in a broken liek manner. (Mario and Lucario come to mind)
Still, if you do the hop, no character is fast enough to punish you, unless you did this way to late and they were already on the ledge to begin with.
aka: You're doing it wrong.
a) It works, I use it pretty ****ed often, its possibly your safest edgeguarding choice without staying on stage.
b) Except for the falcon punch, I wouldn't say it unless I know it to work. (FP works, but its so impractical it's not worth it)
c) Pushing something out as 'worthless' is why boards don't develop. Things have uses, my BAL/BACL for Link boards was deemed useless back in October, and people are starting to finally 'see the light' and see its worth. Maybe this whole b-reversed Side-B will suffer the same fate? Who knows, who cares. If it does, that just gives me more time to use it in videos before it becomes common as hell.
d) Yah, I'm aware of the priority. Most hitboxes are at their end near the edge though, that's just how people try to time their recoveries. Also the angle of which you hit normally let's you hit, rather then your opponent.