> observing dangerous environments like mines, places with toxic waste, and oil rigs.

This could be a good use. Mines in particular where drones would be impractical. I'm not so sure about oil rigs, while Spot would be great on the stairs/ terrain, it has trouble with seeing the edge of cliffs and might well march right off into the ocean.

Probably the biggest advantage would be the ability to take samples or hold some kind of special equipment.