JS is on an extreme end of the spectrum of language inconsistencies, and a lot of developers with extensive experience in other languages strongly prefer not to

JS is on an extreme end of the spectrum of language inconsistencies, and a lot of developers with extensive experience in other languages strongly prefer not to use it. That's partly why there are so many languages that transpile to JS so you don't have to suffer though actually writing it. Further, UI development is an area where things can get messy very quickly. "Safe" languages often greatly minimize the kinds of bugs that are very easy to write in JS. This is one reason why Elm and Clojurescript have had years of adoption -- they by default make values immutable (and their entire programming paradigm doesn't actually require mutating most values ever) which removes a large class of common UI errors. There are other benefits as well.