It's funny he mentions RSI, using a mechanical keyboard with greater key travel distance is worse for RSI than a flat low travel keyboard. The mouse is also much more efficient than the keyboard for many tasks, including in Vim. Reaching for the mouse doesn't affect the muscles related to RSI. In fact, for RSI, I'd say ditch Vim to avoid having to type constantly, since it's just a text editor, and use an IDE which gives you more powerful and automatic coding abilities.