I think it's probably best like you said for situational round-robin things. Or even like you said heal things, but a simple key is probably more reliable for emergency things. I'd like it for things like hearthstone, buffs, bubbles, pets (too many keys for pets, so this is a big one. ie: a different voice command for each pet type you want. or a mix... "tank pet" for making your warlock summon his voidwalker or something)