Comment by duped
It's a fixed size slider which uses the rotation of the indicator to tell you its position, instead of the position of a thumb in horizontal or vertical position.
If you replaced it with text or a bar that filled the area it would be the same.
It's better than a linear sliders because it takes up less space. It's better than a bar slider because you have more range to display (the length of the arc of the indicator is longer than the horizontal and vertical dimensions). This in turn makes it better for putting into tighter spaces.
Your rationals don’t mention users and if you are short on space, that’s poor design — just as a 12” (300mm) bedroom door would be poor design in a dwelling.