Coercion means you only need to define coercion rules in one spot, and existing code can Just Work.
Methods mean you only need to define a method that implements the functionality, and existing code can Just Work.
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Prototypes get rid of the traditional concept of type entirely. Rather than saying "that's an input stream" or "that's an object of type input" we instead say "that's a function that inherits from stdin."
Of course, I don't plan to get rid of types, since I think they're useful (especially with coercion), but at the same time, I think having more fine-grained control can be useful, so I think there's some synergy between types and prototypes.
