There are some big advantages. Integration with an existing system is one -- I don't have to worry about deployment, management, and logging, for example.
You're right that my example program doesn't play to the platform's strengths, but short of spending three months writing a much larger application, I'm not sure what else I could have done to explore as much of the system as possible.
That said, I'm impressed with the modeling tools, and Visual Composer has some huge advantages over most UI tools I've ever seen. Part of this is a sane use of WSDL (where "sane" means "I don't have to think about it"), of course.