It's the combination of geographical data (maps) linked to its visual representation in the world (footage of structures, roads, landscape features) that is useful.

The geographical data already exists in digital maps. And I would expect competent militaries already have maps of enemy territory. It's the second part that was so far missing.

This combined set allows the training of AI models that can say, "When my surroundings look like x, that looks like y on a map".

So when your drone's GPS gets jammed, it can look at its surroundings, reference its (internal and offline) maps, figure out where it is, and navigate.