> I think the smoke serves to make the bees lethargic, and less likely to sting you.

Yes, beekeepers use smoke when robbing a bee hive of honey. It makes BEES think their hive is on fire so they tank up on honey (they have a special second stomach for that) then fan their wings to try to put out the fire. It is really pretty funny to see - the edge of the hive is all lined up with what my friend calls fanney brigades - the bees line up along the edge with all their buts in the air and their wings fanning at full blast. In the mean time it gives the beekeeper time to rob the hive of honey since the bees are distracted and having a hard time flying full of all that honey.

The main point here is that smoke is definitely a BEE THING not a wasp/hornet thing. With wasps the smoke will probably just get them pissed and send somebody to the hospital.