It definitely does work. (at least anecdotally)
If you are in that % where you are just a shit human being and you play this game (or any MOBA) to rage, troll, grief, etc...then there really is no helping you. In fact the only way to truly protect the health of the game is to force CC#s or some form of identification to ensure account uniqueness. Dota does this to some extent with tying the game to a steam account which you would never want to get banned (sure you can just create a new acct, that's why its not perfect but it definitely deters bad behavior on those acct).
As for LPQ, this works great for the masses. Everyone is a little ragey, but once you get sent to this hell there's no way you wanna go back. It keeps you from playing ranked games, and you can make queueing for games take artificially longer.