The more "typical" use for a feature like this is drawing tablets and touch screens. You don't necessarily want a touch/drawing tablet input to move your actual "main" mouse cursor.
I thought this is a bug in the Wayland implementation: I find it utterly unintuitive to work like this. (I just have no idea with whom to file a bug report, which is why I haven't.)
Are you implying that this is intentional behavior?