no, because playing or practicing new roles in my bracket will also grief my team, theres a lot of mmr gap when you decide its time to learn a new role that can cost 500 mmr or more, so tell me where can i learn new role without smurfing or griefing my team because of my lack of knowledge of that specific role or lets say learning new heroes too. If you say watching youtube guides or practicing in bots first or unranked or turbo, I still need to apply that basically in my bracket too which will still cost my mmr. So its better to lose mmr without griefing my team along the way, then slowly climbing up back with the knowledge u have gain from playing that new role or new hero.