Ideally these cases would be caught at compile time, by using a rigid set of types. However in reality it's easier to "defend" against bad input with ArgumentE

Ideally these cases would be caught at compile time, by using a rigid set of types. However in reality it's easier to "defend" against bad input with ArgumentExceptions. Especially if input is a basic string or int, which can be null, negative etc. I guess it's basically defending your method from errors in the caller method, while also keeping it flexible for the caller, by allow simpler unsafe types like strings.