This is still besides the point entirely. Somebody looking to learn web programming is not going to start running a bank. html is on the representation layer,

This is still besides the point entirely. Somebody looking to learn web programming is not going to start running a bank. html is on the representation layer, not a programming language. Modern web apps go much deeper and are using js as as a programming language for web programming that can go much deeper. As an extreme example, Quake Live implements an entire transfer protocol over TCP/IP. In the standard OSI model, there are a few layers between this and that. But there is a reason that purely representative documents still prefer PDF.