i wonder the same thing, those customisation items dont interest me and i would rather sell them in the item exchange

About the customisation items: you can put them on a horse and sell the horse. Some people might even care about the coat and the color of the coat matching the one of the vintage apple.

I'm not sure about any particular reason. For example, except the crown, all the luck items can be traded (and obtained through some divine). So they had to create another luck BMI to make it harder to get. (HoP -> Titans Challenge -> Fleece -> Tyche Crown)
But this time, they made sure they don't have to create another one. So there won't be a divine dropping it and it can't be traded (so one player had to get another 15 by item exchange and get the new divine "for free"). I guess, they wanted all the players to have about the same amount.

That's my theory regarding the luck BMIs.

About the others...
While writing this, I remember having read something like "they regret the item exchange because of some abuse so they won't add any new items to it, but won't take the existing either since players like it". But (even if I remember correctly) this was written by a player as well and I'm not sure at all about the wording. It might just be another theory.

Hello,

This was the official reply from the Dev Q&A, last year:

"Why are all new Black Market items excluded from the item exchange? Will the possibility to trade them ever be added?

� This feature is the source of too much traffic and cheating, so we have decided to stop adding items in it."

Have fun playing Howrse!
AmOwzing