As someone who knows js really well, I love liveview's hooks system. the js interop is the bees knees and lets me save my js chops for where I really need it. Also, I can emit js events that get picked up server side and vice versa. ie: no having to write any ajax calls. My frontend can react to server events with very little boilerplate. Thats a WAY better proposition than merely zero js.
PS: the frontend buildchain is esbuild so you get out of the box support for typescript.