Personally, I have a bad working memory and struggle to remember the structure of data. I constantly have to jump around and try to find the name of things / recall their hierarchy

With static typing I can just highlight a type / jump to the definition or get intellisense. I also find it useful when I have specific names for data types because I can reason about things / communicate them easier

To me taking the time to specify types or wrangle the type checker is worth the reduced mental burden of having to remember the shape of things, and refactor data structures confidently