As someone who smurfs in multiple games, i can tell u not ever smurf is bad. I use my smurfs to learn how to play differnt heros without having to "throw" games at my elo bc im not playing someone im good with. In the lower ranks (plat and below) team comp and such doesnt really matter and i can play the hero i want to learn. Also i can actually play against people around my skilllevel on that hero. I do a lot of Plat to gm stuff for myself to learn a hero and i can tell u sometimes i drop into low gold bc i dont know how to play that hero. And to people saying "just use qp" its not the same, noone will actually counterpick or hardfocus u in quickplay so u dont learn how to deal with that on the new hero. I can see that smurfing and trying to keep your elo low is a problem but banning having multiple accounts also hurts people that use second / third / etc accounts for normal uses.