Clever - I like it.

But the key thing that made rotary dials usable was the catch at the end - it stopped your finger, so you just pushed until it stopped you, and it registered whichever number your finger was in.

Without that, this version isn't really usable. It needs to lock into a draggable state, then keep rotating so long as the mouse is down, even if you drag outside the control. And then it needs to stop dragging at the end, so you cannot over-drag and pick the wrong number. Do those 2 things, and it would be solid.