The AUFS mountpoint is also reachable from the host. However, each container uses its own `mnt` namespace, so further mounts (done within the container) will not automatically be visible.
Docker lets you visualize changes on any container's filesystem live, as they happen. It also lets you snapshot changes from any container into a new image, and immediately start running new containers from that image. No manual post-processing of the image, no configuration files to templatize. The whole thing is 2 commands and maybe half a second.
