It's configurable, but then you have to map the keys you just replaced, and so on. He uses it with the default keymappings. Arrow keys are kind of discouraged

It's configurable, but then you have to map the keys you just replaced, and so on. He uses it with the default keymappings. Arrow keys are kind of discouraged in vim, because a lot of the combo moves (e.g. 10j, y5l, etc.) use hjkl.