For people having the rig in the living room, also heat and noise can be a topic. And a cost of 0.30 is for some countries like Germany already the minimum you pay per kWh.
What is sure is there will come a bill for the electricity, what is not so sure is how the ETH price will develop. So if you want to be on the safe side, I would prefer the lower consumptiom (fix costs) over the slightly better (unguaranteed) profit...