"But elo doesnt tell how good of a player you are,it just puts u in different tiers of skill groups."
This sentence is a complete contradiction, skill groups exists to separate players based on ability so no the elo is there to determine how good YOU are as it an elo scored tied to YOU and YOUR account, so this is a false statement.
"You can still check peoples rating on faceit finder website."
Ok why does this not contribute to rank, of they record this then apply it, use the info you have.
".And lets not talk about pro cs and compare it to faceit cuz there is not much overlap there."
I agree so lets not rank people like they are playing in a team, lets rank then as 5 individuals who want to win a game, so lets take into account their individual performance.