[firlefans]

It's true that it's easier to write and arguably harder to read code when types are not specified, or at least it's handy for public interfaces between modules. Luckily this is easy to do and often done:

https://fsharpforfunandprofit.com/posts/function-signatures/

It's the same deal with Haskell, you don't HAVE to specify the types of your code but it can help check your assumptions as to what the compiler is inferring. I've frankly found that a more frequent issue in Haskell because of pervasive use of Monads and other higher-order constructs.