[devonkim]

It is an advantage in specific situations when you can't rebuild every container or you want to try to selectively update containers without rebuilding them. You should try to update the running containers as a rule but having options is helpful from time to time. In a properly managed container infrastructure it should be faster to update the container image reference before resorting to tactics like this.

[IanCal]

It would be interesting to consider what it'd be like to swap out layers directly, instead of having to "rebuild" the final image.

Perhaps a hack for a free weekend.