I think calling it nightmare-inducing is going too far, but there's nothing that forces you to use it. I think it's fantastic for prototyping, because it lets you focus on getting things done in one place. If you're not prototyping, I think you should keep your JS in JS and come up with a common interface to interact with your JS from the server—I've chosen events dispatched on the document element in a variety of situations as that communication protocol.