In some places it's rare, in some places it's a daily occurrence, and sure you should work towards stability, but the reality is you have to fix this thing now with what you have. There's also the fact that even if it's rare I still have to know it. And if you don't use it often you will forget it. And then why learn two tools if I can do everything with 1? With intellij I can only do day to day, with vim I can do mission critical and day to day. I'd also argue that a seasoned vim user can get things done incredibly faster than a seasoned intellij user.