My in-laws use a system like this, maybe the same one. It uses a CO2 tank rather than burning propane. He runs it 24/7 and he needs to refill the CO2 tank every 1-2 weeks iirc so it's definitely more expensive to run than the death bucket. I think it's a 20 pound tank like you'd see on a homebrew keg system. When he showed it to me, it had caught an absolutely nightmarish number of mosquitoes over the course of a couple days. Like maybe half a liter to a liter in volume squirming around in the net. It made me queasy honestly. I didn't notice anything like bees or butterflies in the trap but I didn't look very closely.