Well...heh...it's more likely that self-use potions should not be usable at all while shifted rather than making the targetable stuff usable in shifted form primarily because it doesn't make any sense to do so. A bear or wolf or whatever would lack the proper manual dexterity to drink or bandage while shifted. Furthermore, your possessions are shifted into your form with you, so it's not like your shifted form is carrying your bag of goodies, wearing your armor, etc.
I think the reason why the self-use stuff is usable and the targeted things are not is due to the fact that the self-use potions are Bioware standard potions, and it would actually be quite a bit of work to make it so they can't be usable.