As a developer it's great. I solves the.. I need a <Mysql, redis, zookeeper> to write code against. So instead of spending my time learning how to be a sysadmin again it lets me focus on other things that matter more (to me at least).

As sysadmin it also lets me sandbox things. Does have a bit of a performance hit, but instead of trying to figure out the various python libraries needed to get mailman running, or any app you can just run it in a container and when you're done your base system is still stable and not polluted with all the crud. Of course it introduces its own set of issues into the mix.