Android does not allow running server on port below 1000 so with dyndns your URL will look funny which is okay for HN crowd but not for people you want to share your blog with.

SSH is doing the port forwarding and Pinggy is just acting like a VPS node so one could just change the port forwarding and/or have NGinx/HAProxy/Apache on the VM could listen on 443 and the Android can listen on any port. Added bonus, the web server could cache the static content to avoid the earth shattering kaboom. VM's are not free but neither is Pinggy.

Most routers can do port forwarding to a different local port

There's presumably no router in this setup.

There would be in a setup using DynDNS, unless you want to redirect people to a closed firewall.