I tried looking and couldn’t see this anywhere. I’ve seen people claim that players will go into the Casual queue to help boost their MMR for the Competitive queue. Then I started thinking about why I would queue for either. For me, I’d probably go into Casual if I were working on a new character or just felt like goofing around.
In both of those cases, I probably wouldn’t want my performance affecting my MMR for the competitive queue, otherwise it’s just tryhard all the time lest I tank my MMR (It’s probably bad to begin with ).