sounds like the kind of thing that programming was invented to eliminate
In all seriousness, I've never worked at a company that did anything like this. What is the use case for creating lots of small apps as opposed to maintaining a larger product?
I don't go learning every language to mastery level, but I try to at least keep track of whereabouts they lie in the spectrum so I can cut through marketing-speak when I see it.
The way I see it, if a thing is being dogfooded in production, it's production grade. People can debate go-vs-rust or whatever till they're blue but the reality is simply that you can ship something with either and there are always going to be proponents and detractors for each side.
While I haven't followed Imba that closely, I've been aware of it for years, and I have to say it's one of few projects that actually has interesting technical takes on several fronts.
Productive, everything included languages/frameworks such as this are great for freelancers, designers, students, and anyone who wants to get up and running quickly. You can also still create maintainable projects with expressive languages (Google and Python, GitHub and Ruby are a couple examples).
People are doing things that don't break with 'productive' languages.
Coffeescript was a breath of fresh air compared to writing ES5.
Regarding perf (performance, I guess?) - are you speaking of the single, global one? As CS takes care of variable scoping automatically, I think it makes a lot of sense (and is deactivatable anyway)
in the sense that you write them and parse them in your brain manually. JSDoc is useful to me because IDE supports it for javascript. Without IDE support it's just a bunch of fancy comments
I see it in less visual clutter.
Someone else may want you to be fast and productive. Or... they'll find someone else who can provide what they want who is faster and more productive than you.