Being able to be fuzzy at the boundaries of your program (e.g., consuming APIs or files) is a lot faster than rigorously defining your types for data un/marshal

Being able to be fuzzy at the boundaries of your program (e.g., consuming APIs or files) is a lot faster than rigorously defining your types for data un/marshalling. Your chickens will eventually come home to roost, but the short-term productivity gains are quite pleasant.