It is an unwritten rule amongst top players in TNT run to never throw slowness potions. Any player known to frequently throw slows has the rage of the entire community directed towards them until they change their ways. Getting hit by a slowness potion significantly reduces any players chance of winning the game. It makes people mess up jumps, your double jumps don't go as far, you can get cut off by literally every other player in the game because they now have a natural advantage over you and worst of all it's completely unavoidable if one player in the game truly wants you to have a bad time. Slowness potions seem to only exist for the sake of a 3rd item in tnt run with the feather and speed potions and it's existence is seen by most good players as a negative when it comes to enjoying the game and this is why it should be removed.