They not only change the keybindings, they change the editor paradigm from a verb-noun model (dw = delete word) to a noun-verb (wd = select word, then delete) model. Multiple cursors also have an effect.

It's pretty close to vim keybindings, but the paradigm change makes it incompatible with 1:1 keybindings.

That said, coming from 15+ years of Vim, I was felt pretty much immediately at home with Kakoune, and dropped right in to Helix with comfort.