That's essentially equivalent to coordinates since you still need to translate it to some human-understandable form, so it doesn't solve the problem.

WhatThreeWords is a proprietary algorithm and has problems with homophones.

I thought W3W was specifically designed to mitigate homophone problems, it seems pointless otherwise...

Yeah, that would absolutely work, but it's not free and donations may or may not cover their costs: https://accounts.what3words.com/select-plan