I find it makes my life easier, personally, because I can set up and tear down environments I’m playing with easily.

As for your user & permissions concern, are you aware that docker these days can be configured to map “root” in the container to a different user? Personally I prefer to use podman though, which doesn’t have that problem to begin with

Podman supports docker compose just fine. You have to run it as a service, so that it can expose a socket like docker does, but it supports doing exactly that

Because a container is only as isolated from the host as you want it to be.

Suppose you run a container and mount the entire filesystem into it. If that container is running as root, it can then read and write anything it likes (including password databases and /etc/sudo)