It is not necessary when you know about the flaw, correct. I bet a lot of people don't know about it.
But it isn't a flaw. It does exactly as you would expect it to: creates a newly named download folder when you change the NZB/collection name and have Alt.Binz set to name dl folder after NZB/collection name.
I grant you that Alt.Binz doesn't account for possible user error here - renaming NZB after downloading has already started - and maybe it should. But you're the only person who has ever reported this, and I can't imagine many having the same problem.
But as always, this is up to Rdl.