I guess if you have a case for running a html+php+nginx workload, you'd build your source code with one (or a list) of the buildpacks and create a docker image and just docker-run it.
Author of the article here. There's no intention here to encourage people to use this in code (in fact the opposite). This article is more of a "Did you know cool shit like this exist?".
It's aimed to a better and neater version. It aims to have separate pages for article in each language, which builds on each edit and thus maintains standalone fully compilable (or one that builds successfully) programs.