I think this explains it very well https://learnvim.irian.to/basics/vim_grammar. You stop thinking about doing specific things tied to a specific keymap and you start to interact with your code using vim's grammar. Besides that, its nice having a consistent keymap between the different IDEs, text editor, browser and shell. Personally I hate if theres a keymap that uses more than a two keys at the same time and I much prefer having a sequence of keystrokes like vim does, I do touch typing so it's natural for me to type a sequence, but if you introduce any modifier key I have to move my fingers from their position. Also, you can find vim in most unix machines that you are going to interact with.