Hidden profiles are against competitive mindset

They did it attempt to break up the toxicity in the game.
Tbf its not standard across all competitive games to reveal the rank. CS:GO/R6 don’t do it, but you can use website to get hold of this data - if you can be bothered part way into the game.

It was useful though to find out what heros were their main so you could pick to counter them in the lobby.