The point is that different languages are best suited to different tasks. Javascript is a simple, very loosely typed scripting language with prototypal inheritance that was developed to be run in the browser. It's a DSL, not a general purpose programming language. Using it elsewhere for applications where another language with stronger and more expressive types would be more appropriate requires hacks like compiling it from another (safer, more strongly typed) language like Typescript, which still results in code that can be fragile because it only simulates (to the degree that a JS interpreter allows) features that the language doesn't actually support.
See the attempt to "detect if something is a Promise" as an example - the function definition for the package makes it appear as if you're actually checking a type, but that's not what the package does.
Most of the unnecessary complexity in modern JS, as I see it, comes from the desire to have it act and behave like a language that it simply isn't.
