It’s not completely pointless, since they can highlight holes in your current play. Yet, it’s certainly not a pleasant nor a fair experience. Those wastes of a player don’t realize they are in fact killing the game by doing so.
That why I created a thread regarding that phenomenon, to inform the players, and possibly draw the devs attention. If you think that issue is concerning, voice your concerns onto it. 
According to some, the smurfing would noticeably drop since D1.
I don’t think there is a league where there are 60% smurfs. Yet, occasionally the randomness of the matchmaking could place you against such amounts. And the worse league tier regarding that had 49%. 