If you set 0 as the value for Capsule Half Height and Capsule Radius, you will get a bug where your character will not stop moving as if physics took over, you have to counter move, to slow your character down and it starts getting annoying as you have to fidget with the movement keys to get the character to stop moving, not to mention what happens if you turn, the character will keep moving in the original direction and will slowly start to move in the direction you are facing as you apply new movement input.
This might be cool for a type of game where you control a ball or something, but other than that…