The jewelry station ARE different, in that other players who don't have Summerset can't use them. I'd imagine the BoP is part of that. It stops you giving or selling it to someone who can't use it.
I can understand them being bound so that players who can't actually use them don't end up buying one thinking that this will give them the access that the stations throughout Tamriel don't. But, as asked previously, why then are the attunable ones NOT bound? It could lead to the same thing with someone thinking that an attunable version would give them the access that ones in the world don't.