What do you get? A bunch of dead ants. It's an odd documentary that praises the glories of this "city" that they have just destroyed, just for the heck of it.
This does seem unnecessarily destructive for very little benefit. That said, it is, admittedly, rather cool.
The National Museum of Natural History recently (in the last few years) had one of these made out of metal. They had poured molten aluminum, I think, into the colony and then excavated it. You could see the ants' impressions in the metal.