Comment by cloverich

I have two genuine, straight forward answers for you. One, I have an important codebase written in a non-typed language, that is heavily developed still. So being able to add types to it (assuming I / team prefer that) is nice. Second is, I much prefer working in typed language, but company forces X language(s) (say, Ruby, Python, etc). Now I can use types (which I much prefer), and not change language (they prefer). Those are both real life examples. Third is hypothetical, but perhaps some people starting without types decide they like them later and want to dip their toes on. Most of these languages now offer incremental types for people to try them out.