Josephson junction is a very interesting device with many uses, including low energy consumption per FLOPS. But one big part of the reason the consumption is s

Josephson junction is a very interesting device with many uses, including low energy consumption per FLOPS. But one big part of the reason the consumption is so low is low temperature. When you try it with room temperatures, switching energy will go up by 2 orders of magnitude (due to higher thermal noise) and this makes the JJ computer efficiency only somewhat better than CMOS. I agree this would still be interesting as refrigeration can be much simpler then and researching JJ-based computers would be easier. But if we talk about best power/watt, the 4.2K systems or 77K systems are likely to be better than room temp superconducting computers.