I am unfortunately so used to vim and its bindings that I suffer whenever I can’t use it. It can be really tricky to do certain operations in other editors.
I just felt that many people may get lost in it when first using it, the same way ppl get lost in vim. At least I managed to get lost in both of them when I first tried them.
There’s a browser extension for IA books. Haven’t tested, but has source on github.