Is there a reason for which some transposing instruments (say, horns in F, bass clarinets etc.) don't have transposing clefs? For some instruments it's not odd to have them, e.g. tenor voice always have G clef with 8va bassa mark, sometimes piccolo or glockenspiel have clef transpositions, too. I've even seen contrabasses with transposing F clef.
I know it's something superfluous, because musicians and conductors know the transposition drill and don't need to have those clefs. But since some instruments still do have them, and it seems purely typographical feature, I'm wondering if there are actually any major downsides that keep editors from using transposing clefs? Apart from technical restraints, of course.