How is this different from what Azure Mobile Services and many others have been offering for the past 2 years? To me it seems the author is proclaiming Platform As A Service is entirely new (look, no spinning up AWS instances!) while this has been around for quite some time, just Amazon is getting into it more seriously recently.
It's also quite strange to spotlight Azure as if it's doing something at all remarkable considering the "Mobile Backend as a Service" market has existed for years and actually seems to be on the decline, at least as a standalone segment.
A static webpage, that calls into a javascript based service, you can register a script to run in that service without any infrastructure hassle, because, well, it's a service.
You are right that there are many comparable Mobile Services that can do many other things and might be branded differently, but this just adds to my point: I don't see what's new here, other than that the OP has seen the light on static webapps combined with platform services.