I disagree too. Frontend is getting more complex each day, and I find that functional programming languages help a lot with large projects. Frontend SPA's are crying for help with the exploding complexity :)
So, if we only want to call a couple of animations and submit a form, I agree that a small script with three jQuery-style functions can do the job.
But that's rarely the case nowadays, in my experience. Almost every frontend project I came across professionally became a full application at some point.
There's the need of dealing with concurrent user interactions, online data requests to the server, non-traditional form behaviors, different routes...
http://banashek.com/posts/20170204-a-brief-peek-at-universal...
Sharing types, validators, etc mean that the api communication is type-safe.