By far the biggest issue isn't just toxic accounts, but "smurf" accounts. Alternative accounts where players don't want to risk their incredibly high rank so they play on an account they "don't care about". You end up. With top 1% players playing at the median bell curve with average players.
You then end up with one player who can solo an entire enemy team of 6, dominating the game; OR being incredibly toxic to his team for not meeting his expectations and throwing the game.
It takes 1 player per match to ruin it for everyone else. In Overwatch, if 10% of accounts were smurfs, you statistically would have at least one in around half your games.
Players eventually can't progress and make progress to get better because the top 1% of players at 4500 SR gatekeep 2800 SR and above.
You then end up with one player who can solo an entire enemy team of 6, dominating the game; OR being incredibly toxic to his team for not meeting his expectations and throwing the game.
It takes 1 player per match to ruin it for everyone else. In Overwatch, if 10% of accounts were smurfs, you statistically would have at least one in around half your games. Players eventually can't progress and make progress to get better because the top 1% of players at 4500 SR gatekeep 2800 SR and above.