It means I have to sit and read through the Dockerfile (or compose, in many cases, which is even worse) and figure out what its doing and what magic variables I

It means I have to sit and read through the Dockerfile (or compose, in many cases, which is even worse) and figure out what its doing and what magic variables I need to provide etc, when just providing a binary download url and an example (or reference) config does just fine, not everyone uses docker