Who knows? There's always uncertainity, and a non-zero probability that the bombing site happened to have a geologically interesting cave system underneath, or a hidden cache of alien artifacts. The probability of such a thing, while non-zero, is really low, and we also don't observe fragile systems on the Moon. It's simply a dead rock.

As for bombing Mars ice caps, that was a nice idea too, IMO (even though AFAIK it turned out to not be useful). The goal here was to densify the atmosphere with water vapor and CO₂. Assuming you consider terraforming Mars a good idea, doing it in reasonable timescales will require some preparations involving direct applications of lots of energy - whether it's melting the ice caps, or redirecting comets to hit the planet. At some point we might be able to accelerate the process by deploying bacteria and plants (read: self-replicating chemical processing nanobots), but the conditions are not right for this yet - hence the ideas like using nukes or comets to bootstrap those conditions.