TIL I'm not a serious developer. I actually think compiling Javascript is a huge barrier to entry to would be devs. I think a development experience of put the code on the page and it runs is a lot better than configuring npm/gulp/grunt.
But if you're writing complex business logic, trying to build pipelines of client-side data whose derivations are fed into a myriad of components, and you'll want things like type constraints, module hierarchies, compiler support for things like JSX to simplify the cognitive load of understanding what a thing-that-outputs-HTML-like-stuff does.
At the end of the day, compiler setup is O(1), and code complexity is at least Ω(N) in how difficult it becomes to understand a codebase. It's worth doing anything you can with the compiler to reduce complexity in large codebases.
The problem is that this breaks down immediately for a million different reasons at any kind of scale with multiple developers, complex dependency graphs, and the need for automated testing. The tooling exists to solve real problems whether you've experienced them or not.
I also think you right. Compilers don't always go well with programming inductees. This is why Python and Ruby are so popular as introductory courses. But this is why I think Javascript has done so well because it doesn't _need_ compiling, which is great for new-comers. When things level up and get complicated, enter JS compilers. It's a 'best of both worlds' sort of thing.