> Q: Why don't you just learn the vim commands?
> A: I did, but if you don't use vim regularly, you keep forgetting them.
The basics are only useful in vim, and editors that you force into vim mode. Other places one types text into which use the same conventions absent in vim: browser input fields, the url bar, email, office software, random input fields in games (I've seen single file libraries that obey the same conventions of moving across words that you get in office), publishing software, chat clients... Vim is the only outsider, and because I only need it rarely, I forget things and I accidentally use the shortcuts from other software which sometimes break things.
I know enough vim, but I keep using conventions from other software out of habit, and shortcuts do other things. Vim is great editor, but a horrible thing to use by default simply because it was made before text editing ux got standardized.