@Riot, so why cant we know our exact MMR?

(Before you get your pitchforks and torches, the only reason i am comparing them is because they are the two biggest and they are having the longest "history")

Dota has this stuff, if you ranked you see it, no shady algorithms, no need for a site like op.gg, heck they even shared how they are doing it. And here nobody know anything for sure, and it wouldn't hurt anybody, I mean, I wont win more games cause I know my MMR, yet I will know which skill level do I stand on precisely...

What are your thoughts, do we need it, would it even matter for you?