Docker is amazing. Containers make setting up a media server almost like building with LEGOs. You just pull down the image you want (likely from the great linuxserver.io), make sure you wire up the ports and volumes appropriately, and Bob's your uncle.

Sometimes what you want to do isn't packaged up in a nice Docker container for you. Docker is still helpful in these situations.

I don't know about you, but when I'm experimenting with something, I am always weary about installing stuff because I don't want a bunch of trash hanging around on my server when I'm done. There's always chroot'ing or lxc, but I've found that generating a customized docker image and spinning up a new container when you need it is easy and makes cleanup a cinch.