I suppose it could be useful, but not being able to evacuate someone certainly limits what it can do. In the video they still needed a helicopter for the actual rescue part.

For search drones are cheaper, scale better, and are safer for mountain rescue staff. This may make sense for whatever cross-section exists for remote mobile first aid where a helicopter is unavailable, and you roughly know where they are (due to limited fuel and the risk of the jetpack itself getting stranded).

If it can be expanded to hold two people this could be incredible for rescue.