I'd like to use Rocket personally (I currently use Docker--while I think CoreOS's "containers everywhere" concept is a little misguided, I don't believe there's a good reason to have a permanent daemon, and if I need one I have Mesos) but make things I do easily available to Docker users.
(Docker's beefs here feel more like a company defending their turf than an open-source project, and that troubles me.)
If I were a Docker user, and found some awesome app that only came packaged in App Container format, it'd be very valuable to have this compatibility.