the biggest selling point for me is that I'll have a mounted folder or two, a shell script for creating the container, and then if I want to move the service to a new computer I just move these files/folders and run the script. it's awesome. the initial setup is also a lot easier because all dependencies and stuff are bundled with the app.

in short, it's basically the exe-file of the server world

runs everything as root (not many well built images with proper useranagement it seems)

that's true I guess, but for the most part shit's stuck inside the container anyway so how much does it really matter?

you cannot really know which stuff is in the images: you must trust who built it

you kinda can, reading a Dockerfile is pretty much like reading a very basic shell script for the most part. regardless, I do trust most creators of images I use. most of the images I have running are either created by the people who made the app, or official docker images. if I trust them enough to run their apps, why wouldn't I trust their images?

lots of mess in the system (mounts, fake networks, rules...)

that's sort of the point, isn't it? stuff is isolated