I tried hard for a few months to be efficient with vim. At the end, I was still faster with a laptop keyboard and trackpad for selecting and editing text at arbitrary places in a document ("random access editing").

One case where I find a mouse/trackpad essential: editing LaTeX documents. Being able to control-click to jump between a spot in the compiled .pdf and the corresponding source code, or the reverse, is invaluable (a feature supported in TeXShop, for instance). I realize that one can probably set up a similar system in vim. But, the appeal of vim for me was that, at the cost of learning a bunch of arcane keyboard shortcuts, I could go mouseless and as a consequence be faster. If I'm going to keep the mouse, the value proposition seems a lot worse.