How useful would Mac-native docker be? You couldn't run any of your Linux containers and I cannot see much utility in macOS containers.

Plenty of people develop on macOS and deploy on Linux (this isn't completely reliable but people consider it good enough for Ruby/Python/Node.js) so I could imagine a portable Dockerfile that generates either a macOS image or a Linux image depending where it is built. This would speed development dramatically.

But isn't the whole point of Docker having a 100.0000000% repeatable environment? And how would that portable Dockerfile would look?