The #1 reason to use a mouse for me is to do input you can't easily do any other way. The first is hover info for things that are't anywhere near the cursor. I

The #1 reason to use a mouse for me is to do input you can't easily do any other way. The first is hover info for things that are't anywhere near the cursor. I don't want to move the cursor in order to hover an identifier 20 lines and 40 columns away. Because once I have hovered it for info, I still have the cursor in the right spot. BUT, that I can also do with a trackpoint/ball/roller/whatever. The most important mouse thing is for freehand input like drawing. It's just not ergonomical to do that kind of thing with a trackball. Using any kind of pointer to move a cursor in text or navigating to a different window or a different textbox isn't really a good idea. That's done better with a keyboard. But the thing most keyboard purists overlook is the thing they don't do at all (draw, hover), so they don't miss it.