All that stuff could probably be done with apt, yum, dnf or any other package manager though. The reason they're better is because you have some fairly skilled contributors acting as the gatekeeper of the projects.
Now the nice thing about docker is you could have spent about 5 minutes to trivially docker run the app, decide if it's actually worth the effort, then untangle the mess beneath.
That's a net win in my eyes, though by the time I actually run something in production, I generally try and untangle the mess before I do. I also find it's easier to get help developers deliver something legible as sadly many of them often don't even know which packages they installed to get something running.
Listen, I'm not saying it's perfect. I specifically really don't like that Docker is basically root without Selinux (which is often turned off). I'm happy to see docker be replaced. I am however, not really interested in returning to puppet modules to handle dependencies when a container is, in my opinion, so much better.