What are reasons to choose a scripting language over C#?

Question

What are reasons to choose a non DSL scripting language over statically compiled language such as C#?

-edit- Good answers so far. I feel I should explain further. I

Answer 1

1. Flexibility: you don't have to worry about the static type system.
2. Speed of development: an interactive language allows you to write code and test it faster.
3. Built-in types: usually script languages provide dictionaries, lists, tuples, sets, etc. as part of the language (not libraries) with syntax sugar that can be very handy.
4. More dynamic features:
   1. you can "eval" code at runtime very easily.
   2. you can replace on the fly functions and methods.

The main drawback is that those features are often too powerful, and without an strict discipline it's very easy to write code that is unmaintainable.