Only three ways to move the mouse seems relatively tame compared to the forest of Linux API calls when it comes to input (depends on X11/Wayland among other things). Also, your last link clearly states that the API call has been superseded, so if you follow the documentation you only have two options.

I don't think the difference between the two is all that strange. One sets the position of the cursor, the other interacts with the system like a normal mouse. The mouse and the cursor are separate things, and they're handled at different levels in the API stack, like XSendEvent and sending data to libinput.