Docker - what use is it?

I don't get the question... Docker is awesome for developing, but to put things on production too. It just avoids you the hassle of configuring a virtual machine / server from scratch since you can use prebuilt minimal images of the software you need. If you get in trouble you can restore things easier than on a whole compromised system. An update consists in the vast majority of times in changing a tag inside a docker-compose.yaml file. You have resource optimisation vs virutal machines, and so on. I don't use docker to develop at all, I use it for production. And when you don't need the service you installed anymore, you can just delete it and the system stays clean wihtout orphan files.