Both this and other PaaSes remove a lot of the plumbing. Also, the target audience is different. PaaSes offer self-servixe for end users: for instance starting

Both this and other PaaSes remove a lot of the plumbing. Also, the target audience is different. PaaSes offer self-servixe for end users: for instance starting a new database on demand through the user interface. You can achieve much of this with Docker Compose, but your users can't. The Docker-PaaS movement reminds me of content-management systems in the early 2000s. Everyone (myself included) thought it'd be great to spend loads of engineering effort reinventing the wheel, instead of delivering business value.