The principle in a docker container is to not care about the inners of it, since you are not directly connected to it (besides setting up the app).
The goal of @damian, I think, is not to test if nodebb runs well on a platform but rather to have a small image to run tests against nodebb and maybe some added plugins, etc. To this, the smaller the container the better, and alpine is good at that.
And even for production purposes, if you want to setup a farm of forums, the smaller the image the better.
I hope this sheds a new light on our request.