No, my bees don't have bronchitis. I don't either. It's for mite treatment of the hives, if, or when it becomes necessary.
Another $125 USD added to what I have paid out for beekeeping. If, or when I begin having problems with Varroa mites, I will have something to combat them with. So, why did I buy it before I have a mite problem? Well, because it took one month, to the day, to arrive from the US. I would rather have it and not need it, than not have it and be in a world of poo-poo.
Definitely a tool to have on hand, along with the Oxalic Acid that came with it. This little jewel, when connected to a 12vdc battery, of suitable Amp Hour rating, will heat the acid up and turn it into a vapor. The vapor will then move throughout the hive and destroy the mites, without harming the queen bee, the bees, their brood, or their stores. (You would not keep honey supers in place during an OA treatment, though. They would need to be removed from the hives and all bees taken off the frames.)
After treatment, you would repeat this process two more times over the same number of weeks, to make sure the hives were cleansed of the vast majority of mites.