To those that have tried the browser or investigated the project more, what is the utility of this browser over, say, Firefox with a vim plugin[1] that lets me

To those that have tried the browser or investigated the project more, what is the utility of this browser over, say, Firefox with a vim plugin[1] that lets me also navigate with a keyboard? I am all for new browsers and believe that hobby projects don't need a reason, but I am curious what distinguishes this over something that can be achieved with plugins in a more stable platform. [1] https://vimium.github.io/ https://vimium.github.io/