The goal of TypeScript is to be a type-safe
superset of JS. Removing these type hints and aids
directly, you simply have JavaScript.
> Why can't we use TypeScript on the server side, maybe the main language in Node.js or maybe standalone, or directly in the browsers without transpiling?
Then you'd end up with the same story as Dart, a language that aimed to solve the shortcomings of JS.
Afaik, it was a totally different language. It was able to compile to JS, had its own engine, Chrome almost shipped with that engine, even had a browser with that engine (Dartium).
But nobody went for it, and the hype quickly died out. The same story with Go, until the hype subsided and everyone either continued using it, or made fun of it.