This is exactly my experience. If your project doesn't have a nice build pipeline for TS then it can become quite awkward and take more work, especially if you have isomorphic code that isn't all in TS already. Also, a lot of the interface syntax can get pretty weird when you are trying to type untyped libraries, which definitely slows me down. I love types in languages like java where it feels like the types have first class support--but TS by definition often involves calling out to libs that aren't written in TS which feels awkward and loses a lot of the advantages.