I dont know what the net load is for a blimp, but if they could somehow carry 100-400 people, why coudln't they be used like ferries in metro cities like SFO and NYC? Even if they could only scoot at 60-100mph, they can cut clean across waterways and save a ton of time for commuters while (seemingly) being more efficient than fixed-wing aircraft as well as safer (engine failure? gently float down and call for help).
A bonus would be if they could convert their balloon into a flying wing shape in flight via compressing the gas, reducing volume, and having it fold into a wing-shape allowing them to increase speed. If they could get near 200mph, that could open up decent commuter service between LAX <-> San Diego. But even 60mph could connect the greater Los Angeles area. If the weather were bad, a cable-tethering system could be used to guarantee smooth landings (fly into the tether, grab it, command the cable to retract, thus pulling the blimp into the station).