There are many benefits to the PS4 acting as a client to a cloud service that the Playstation app communicates with.
There is literally no benefit to PS4 acting as a webserver for the Playstation app.
The only reason they would make it a PS4 webserver is that they aren't able to scale their own infrastructure up enough before launch.
That isn't a permanent problem, and they said it might possibly change in the future.
But it is certainly not a good sign of their cloud infrustructure.
You can. If you open whatever port the PS4 is using on your router.
We do know you can remote purchase on Xbox One.
Xbox One acts as a client to a cloud service, it can open a connection to an external server no problem. Smartglass also act as a client to a cloud service.
PS4 is an intermediate server between PS App and PS servers, you'll have to mess with your routers port security to access it thru an external host or else your router will block your request to the PS4 web server.
Yep. That's it tho.
Smartglass does the same thing but with wifi direct if you're near your Xbone.
Link?
I've never seen it confirmed that you can remote-start downloads.
You are also making a TON of unsubstantiated assumptions in that post.