Not OP, but I've been using vim for 20+ years and I get enormous utility out of the mouse wheel for scrolling - especially with a trackpoint.

I spend an enormous amount of time _reading_ code and I want to move up and down quite a lot, but C-U/C-D move too fast (losing mental context) and C-E/C-Y are too slow and RSI-inducing; the wheel very easily allows you to encode an additional "velocity" dimension that the keyboard simply doesn't have.

When reading code, the mouse also allows you to navigate reasonably effectively using only one hand, leaving the other hand free for sipping coffee and taking notes.