I have become jaded with publications that hedge like this. In my experience most of these discoveries never pan out, they just disappear. And not being in the field myself, I don't know how to judge.
Does anyone in quantum computing have a read on how big a deal this is (or isn't)?
7K is considered “warm” from a cryogenics point-of-view because you can just dunk your sample into a dewar of liquid helium at 4.2K. You can even get it cooler, down to about 1K, using evaporative cooling techniques. [1]
It’s getting to lower temperatures than this when things start getting complicated. Eg a closed-cycle evaporative He3 system can get you down to 200 mK, or you can bite the bullet and use a dilution fridge down to around 10mK.
(There are probably a lot of other nasty details, but less than 4K is harder.)