That's for the founder to figure out. I imagine that with a 'pivot' on the scenario that the product is being built for, there would be change in its form (both hardware and software).

But this comment makes me think, why this product cannot exist as a mobile walkie-talkie app?

When "war" comes, the "army" launches the app and are plugged into the dynamic war operations, using a headset. When the war is hopefully won, everyone goes back to their peace time apps - Email, Slack...