It's a bit scary to see that one of the highest-voted answers to this question (188 points) is completely wrong. It says that the (0,0) hotspot simplified the calculations for a cursor position update, because you didn't have to add any (X,Y) offset. https://ux.stackexchange.com/a/52349/43259 The problem with this idea is that the arrow pointer was never the only cursor. On the first Macintosh, there were many others…
The scary part is that you will likely be saying it again in another ten years and again and then you’ll die as “that weird cursor offset obsessed fanatic”.