Could you explain the brilliance of prototypes? Prototypes in JavaScript are pretty awful, but I've never been sure if that's just the JavaScript implementation

Could you explain the brilliance of prototypes? Prototypes in JavaScript are pretty awful, but I've never been sure if that's just the JavaScript implementation (for instance, the lack of a good way to clone an object makes using prototypes in JS more painful than it needs to be), or the concept of prototypes more generally.