They'd be great at secondary recovery once they get into place but they're so slow you can't use them for the immediate recovery and life saving efforts unless they're immediately in the area.
A Zeppelin NT can reach up to 125 km/h, that's way faster than any truck can possibly reach in a disaster zone. The only thing faster and as versatile is a select breed of cargo choppers like the Mi-26 (Russia) and the CH-53K (US), but flying choppers comes with risks on its own from rotor downwash.
They're faster but they can't lift much at all. Their payload is only 1,900 kg while a CH-53K can lift a bit over 16,000 kg.
Yeah basically only useful as cargo lift and maybe as mobile medical facilities.
They could maybe act like mini versions of the hospital ships run by the US and others for inland areas beyond the reach of ship based care. Still kind of runs into the response speed issue. In the time it takes a blimp to trundle over from wherever it's stored helicopters can deploy a lot of materiel.