I think it's representative of the ability of a civilization at that point in time, to think in the long term, having the capability to join knowledge with economic resources through the will to improve the lives of people. It brings the modern day into stark contrast, where we seem to have many critical areas where we are awash with knowledge that is not meeting up with the economic resources and the will to make progress.
This seems to be a problem both at a grand scale, climate change, and more local scales like the Oroville dam. As a technology alone, the cistern is neat, but the building of it, and later abandonment has maybe more to tell us in the long run.