How else can you get comfortable with something different that is potentially better than what you're currently using?
Learning Emacs or Vim is an investment, one that last your entire life. I will gladly be less productive for a few weeks to gain much more in the long run.
It could be argued that they also cost a lifetime to learn. With normal, full blown editors (eg: editors that require Java) I get a ton of intuitive functionality for free, and I can start using it right away.
