For the calculation, I take the price of electricity at $ 0.04 per kilowatt. This is the price of electricity in my city (Russia)
With the firmware, this ASIC will give $ 3 profit per day.
Getting $ 3 profit from 0.8 kilowatt seems to me not the best idea, and if you pay more for electricity, then it is not interesting for business.
In 24 hours on 3 machines I made $11.98 total is all prices are good each month 3 should make about 135-150 profit @ .12 kw.
So if you have a large number of them sitting around that is a decent profit a month