I've been interested in deploying something like this around my property to localize sounds that I hear just for fun.

IMO having the on-device model to pre-filter to the signals of suspected drones is potentially a good idea in a wartime environment. Not only does it conserve bandwidth (which might be a limited resource), but it also reduces airtime and thus makes the devices harder to spot.

GPS is also unreliable in Ukraine, especially near the front line.

It's unclear which approach would be better from a power budget point of view. One requires substantially more local processing power but much less radio time, while the other requires continuous radio transmission.