Vim, at its core, is a language for manipulating text. When you "think" in Vim, you are writing small one-off (or stored, in the case of macros) programs to do something to a text file. Once you become familiar with the basic building blocks, you can construct complex text manipulation commands on the fly. I've found that while programming I often spend more time reading or thinking than writing, but when I _am_ writing, I usually bump against an input bottleneck as I generally have a good idea of the changes I want to make. Vim speeds up that step.