I was looking at the opto endstop and wondering: Is it really necessary to have an optical endstop or would you be able to do the same thing with a points system?

I'm not sure I follow. You don't like them being optical, or you don't like them being there at all?

Something needs to provide a notion of a 'home' point, and be able to inform the controller when the toolhead is home. Stops at the non-home end of each axis would just be failsafes though, and are already considered optional as things like the extruder valve solenoid are driven from pins formerly used by those endstops.

You need to be able to reset the positioning system to base. Some means of doing that is mandatory if you are to get anything like accuracy in printing. Whether the opto endstop is the way to do that is a debatable issue.