Good enough performance, overhead is fine, easier to read, faster development time, vastly easier exploratory prototyping abilities, dynamic patterns available

Good enough performance, overhead is fine, easier to read, faster development time, vastly easier exploratory prototyping abilities, dynamic patterns available that can't be done at all in static languages like meta classes and dynamic message interpretation via late bound message passing. If you don't understand the appeal of dynamic languages, it's likely because you still program like you do in a static language while in them and you're ignoring the new things you can do that you couldn't in a static language. Static types are handcuffs, they prevent all kinds of perfectly valid code that work fine in dynamic languages. Static types ensure you don't make certain kinds of mistakes, but the cost of doing that is forbidding valid code that can't be verified at compile time to be correct, even though it'd work fine at runtime. I want to tell the computer what to do in the simplest form possible, I don't want the computer telling me what to do, and I don't want to have to decorate my intentions with a bunch of unnecessary type fluff to make a compiler happy, and I certainly don't want the compiler telling me I can't do something I know will work perfectly fine just because it can't be statically verified.