I see this done for bee queen so often. If set up for Dragonfly this would be the best gem farming method, but for some reason I have never seen people do it. You do need to kill the Dragonfly at first to do this, and then have 20 days to create it, but if you get everything you need beforehand, why does none do it? Because it's a fun fight?
Bee Queen constantly gets cheesed for some reason. There is a level of interactivity, I guess, but for some reason people seems to leave other stuff to kill Bee Queen in a state of "auto-farming" much more often than Dragonfly. I guess when you have tentacles around, you have the choice to fight her yourself or let the tentacles deal with her, or something in the middle, while with Dragonfly, you may not have that choice, but that could still be set up, so why don't people use Tentacles? Read about ~20 books of On Tentacles and you'll be auto farming gems and furnace blueprints for quite some time. It'll take about a minute for her to die, as most of the health would already be taken away before the first time she starts to spew lavaes.
It may be more often than I think, but usually, it's jut a wall across a pool of lava, where you yourself have to take part in beating her, and can't just sit out the fight while doing something else, save some time and just grab the loot once the boss is killed.