As far as I can remember the inverted (aka "XOR") style of mouse cursor has been around as long as there have been mice. I mean something like this:
where the cursor shape is formed by dynamically inverting the colors of the individual underlying pixels. I'm pretty sure I saw this on Macs in the 80s and early versions of Windows.
I don't recall the exact methodology of forming the inverted image but I think it was based on an XOR bit manipulation.
Personally this is not my favorite style of cursor graphics, but tastes vary & I'm sure many people must like it. However given that there are also more standard solid black or white cursors this must have taken someone a bit of additional work to implement. And on top of that it seemed to become universal to have this style of cursor. That makes me wonder if there was some reason for it other than individual preferences?
Googling around this topic I gather there was even once some controversy over patents on this idea - more 'evidence' that there was a really good reason for it to exist?