Is the geographical data more useful, or are buildings and other structures more important?
Genuinely don't know much in this space.
You also need a day/night dataset (although some newer descriptors are day/night resistant)
Have you ever seen a commercial use of anything like this? That should give you a hint about how reliable these systems get.
Shops come and go, churches do not move, schools tend not to move much, industry areas is somewhat dynamic, military installations might be static or dynamic, trees grow or are removed.
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.
Niantic has the benefit that they can steer "volunteers" to specific points, though.
... Except, well, when it's the doing of this same, so called "defence" industry.