Good idea..for huge caves. I've been caving for 30+ years and I can tell you that a skilled and well equipped human will be able to explore more than one of these airships. Sometimes passages are obstructed by ceiling collapses. ( after water drains from the cave due to the lowering of the base level rock will fall off the ceiling due to the loss in buoyancy). Sometimes one needs to move a few rocks to get by. Sometimes you just need to squeeze and contort to get through. Sometimes you need you dig a bit of sediment because it fills a passage to the point of preventing preventing access.

Having said all that, the one time when this would be helpful is when you enter a space with an extremely high ceiling. One can bolt up the wall see see what's there. But the better/easier way is to use a drone to do recon first.