Transmogrification on offset items?

Hello, so I am wondering here if there is a reason for us not being able to transmog necklaces, rings or trinkets?
I do understand most people see no use in it, as it wont change an already visible gear item outside but is there harm for enabling it? I for one would very much love the ability to make use of old unique model icons that are on some old trinkets and such.

Sorry if this has been answered elsewhere, I tried searching but didnt manage to find anything useful