You’re mixing apples and oranges here.
First, a dirigible of any sort could function as a flying crane, carrying cargo suspended below it – no problem with the concept, and the points already brought up about what happens if it is involved in an accident. But it would be my presumption that with very rare exceptions (moving big generators to rugged hydro sites, for example) you’d do interior cargo carrying, much like an airplane – you don’t sling the stuff beneath a C-5A, but load it inside it, in a cargo space.
Second, there are two (actually three) classes of dirigible, which are as different as a kayak and a hydrofoil. A blimp is a giant fusiform helium balloon with attached gondola – you inflate the balloon, and ride in the gondola slung below it. You load the cargo into the gondola too – and you need a relatively big gondola to hold everything.
But a rigid airship, like what the Navy flew in the 1930s and the Zeppelins, is a bunch of balloons inside an aluminum frame, which need not take up all the space inside the frame. Normally the bridge of a zeppelin was in a gondola in the normal location – attached to the front underside of the hull – but it need not be. And passenger and cargo space were located largely inside the frame, in areas where lifting cells were not mounted. The disadvantages of zeppelins were that 1920s and 1930s technology was not adequate to build a ship that would stand up under strong windshear (though the Graf Zeppelin and the Los Angeles, German-built, did better than any airplane of the time could, and never crashed), and that you do have the parasitic weight of the ship’s frame to contend with. But in terms of added cargo and passenger capacity, the latter is far offset by the advantages, and I’m quite confident that 21st century metallurgical technology and engineeering can overcome the windshear problem.
The idea of a flying cruise liner capable of doing 100 knots or hovering and passing over either land or sea makes immense sense – from the accounts of wealthy 1930s people, there was nothing comparable; it combined the best aspects of an airliner flight and a ocean cruise, with the added advantage of absolute stability – nothing would disturb an airship in flight, unlike wave action or air turbulence (the latter of which it was large enough and slow enough not to be bothered by).
Cargo carrying, it’s debatable whether it could compete economically with airliners – at present. Although if the price of aviation fuel continues to rise, those who need to ship something relatively fast and inexpensively may think twice about their investments.
I’d say that technologically there are no dealbreakers, and economically it would make sense to build them – but there’s still a lingering memory of the Hindenburg as nearly the sole public knowledge of zeppelins – and no recall of the long and nearly problem-free careers of the Graf and the Los Angeles.
