Docker's what lets me spend more time using the software on my server than fiddling with it. I got the fiddling out of my system years ago, I just want shit to work now.
I don't really care about it per se but having a cross-distro unified daemon config & supervisor, package manager, and ability to cram every single important file into a file tree (again, using the same interface to achieve this with every daemon) that has only those files in it (making backups and restores trivial) and then easily verify that I got all the important files (destroy image -> re-create, does it still look good? Then I got everything) makes everything so easy. I no longer put off trying a new service until the weekend because it'll take an unknown amount of time that could end up being hours. Odds are I can have anything available in the official Docker registry (which is approximately everything, these days) up in five minutes flat to try it out, and may not even need any further modifications for it to be ready for (personal) "production".
I use Debian but don't even care, I haven't had to touch systemd once (thank god) and the only Debian-parts I even use are its ZFS, SSH, and Docker, with my ten or so actual user-facing services all just pulled and managed via Docker, ready to transfer to any other distro seamlessly, should I ever care to. Even Samba is under Docker (oh my god it is so much easier to configure for common use-cases this way).
(I would definitely be using FreeBSD on my server if I cared about anything other than Docker, though—I haven't actually liked Linux for about fifteen years now)