Indeed, that Docker is functionally a cross-distro rolling release package manager, configuration standard, and service supervisor[1] is the appeal to me. Any isolation it achieves is necessary for that to all work reliably, but is not why I use it.

Inability to find a service I want to run on Github and 95+% of the time to be able to configure it and have it running and fully managed with usually just a one-liner shell script like 10 minutes later just by finding an existing docker image is the thing I’d lose with jails. That’s all of the value of docker to me personally. Jails could be a building block toward that, but last I checked there’s no deep and up-to-date library of “packages” I can reach for, using jails, which makes it pretty much useless to me.

1: I have like eight or nine services running on my home Debian system, they all auto-restart and come back up on reboot, and I’ve not had to touch Systemd once on that machine.