I'm a Rubyist at heart like DHH so I get not liking types, but after being involved in a pretty large Rust codebase where everything was typed and having my editor be able to know exactly what I'm trying to do in 99% of cases, I find it hard to go back to Ruby, especially if we're talking about a team setting where you're working with other devs. If I'm doing something solo I still prefer Ruby since I can just write the code and forget about it.

I've also had the pleasure of working on a JS-only project, and I would've killed to have typescript there. It was anyone's guess what any method call would be doing, what arguments were being passed around etc. I can't imagine working in a large JS codebase, especially with other contributors, without types to back you up.