Just like the mouse that has to be polled 100 times per second or display that is composited from all window buffers at least 60 times per second. It might really be negligible in the grand scheme of things and not worth optimizing for.
You cant imagine how much strain fast-moving mouse cursor put on display server of almost any OS if there a lot of windows open simultaneously. Also non-standard cursor sizes / formats are still such a mess everywhere since even in 2026 there are semi-hardware and software cursors...