i don't think they're not distinct, but to anyone who doesn't really care that strongly about the nuances of either 'just squash the two small humanoids together' very easily sounds like a reasonable enough solution, that doesn't mean it is though, but i mean hey, while we're condensing species why not shove the two strong species of orcs and goliaths together into a single species right? it's not like they've got their own distinctions, or maybe the magically inclined elves and githzerai? and there's no point in having both aasimar AND tieflings? get rid of all these unnecassary statblocks cluttering up the books.