The strongest benefit of static types for me is: You can have different forms of polymorphism if you have static type information. For example, the visitor patt

The strongest benefit of static types for me is: You can have different forms of polymorphism if you have static type information. For example, the visitor pattern from OO-languages is obsolete in languages with enough type information available, because they can just dispatch on all argument types. For example, python or ruby cannot do such a multiple dispatch without any extra effort.