Others have addressed the root and trust questions, so I thought I’d mention the “mess” question:
Even the messiest bowl of ravioli is easier to untangle than a bowl of spaghetti.
The mounts/networks/rules and such aren’t “mess”, they are isolation. They’re commoditization. They’re abstraction - Ways to tell whatever is running in the container what it wants to hear, so that you can treat the container as a “black box” that solves the problem you want solved.
Think of Docker containers less like pets and more like cattle, and it very quickly justifies a lot of that stuff because it makes the container disposable, even if the data it’s handling isn’t.