[handrous]

My personal favorite thing about Docker, and the part I'd most miss if I switched to Jails (which I'm fairly confident could meet my needs with some fairly simple scripts and aliases that wouldn't take me long to arrive at, which is why I think there's so much less of an "ecosystem" there, even a nascent and under-developed one) is the way it forces projects to un-fuck their configuration.

500-line config, much of which few people ever care about, with all kinds of ill-conceived nesting? Better put the ~20 options that 99% of users ever touch in environment variables, and document them. Weird state garbage that's not captured in your config-on-disk? Better figure it out and get it into env vars, and have your startup script use those to transparently manage whatever bad decisions you made re: state in the past. Shit files all over the system? Better get that sorted out so people can handle persistence with at the very most three total mounts—and oh, gee, look, now your simple example docker-compose also serves to document where exactly you store files. And so on.

(my second-favorite thing is that it's a de-facto cross-distro package manager with very up-to-date packages that are trivial to completely and cleanly uninstall)