Did you search on the zone for cryogenic treatment? It has been discussed before.
With HSS tooling there does seem to be a positive effect on tool life and if you do some reading on the subject there is a rational metallurgical explanation. Briefly explained, when metals are heat treated to get a particular crystal or phase structure there are always microscopic regions which do not complete the transition during the cooling process in the treatment. This gives minuscule variations in the properties of the metal and it is these variations that lead to faster wear than would be the case with a metal that was utterly identical all the way through. Taking the metal down to liquid nitrogen temperatures, -196 Celsius I think, forces the crystal transition more toward completion so the metal has a more homgeneous crystal structure.
I know people claim that it also works with carbide but I do not know if there is a similar thing occurring; carbide gets its hardness by a completely different mechanism than HSS. But it is possible that cryogenic treatment has an effect on the structure and strength of the binder in carbide tools even if it does not affect the carbide itself.
An open mind is a virtue...so long as all the common sense has not leaked out.