Well......not really. Using the air shocks to level a car out with a heavy load that it probably was not designed to carry puts more load than "just raising the car, because it has the weight of the car, PLUS the load pushing down.
That said, I'm not condemning air shocks. Tons of them have been used over time quite successfully. But IMO, if they are used as intended, to level out heavy loads, it should be only temporary and not something done all the time. The repeated use in that situation is what will beat the shock mounts all to pieces.