regardless if you hear a difference. To me its not worth the potential damage to the tube or its longevity. these tube are getting expensive and NOS tubes are ridiculous now so anything that could shorten the life of a tube is something to consider.
Comparisons to other uses of cryogenics is irrelevant as those uses are documented to help i.e. straighten the structure etc.
Short duration blind testing has proven scientifically to NOT be a reliable test for audio/sounds, humans need a prolonged period to hear the differences. short time frame blind testing is not a reliable way to test sound/hearing of humans.
The NRC in Canada has out lined preferred testing methods, and even in those professional listeners have a hard time telling the differences in short duration blind testing. I think the NRC has a very good system for blind testing better then anything else I've read about. But very hard to implement in a user setting as it has rotating floor sections that rotate speakers through the listening position behind a acoustically transparent curtain.
Anyway I think the article has merit and should be considered when buying tubes. Also of note the listening test they did in the article were with guitar amps not audio system amps. Not sure if that it better or worse for detecting differences.