don't know if Galley Swiller is an engineer or other - but his facts are straight.
metals do certain things at certain temperatures. boiling water (aka 212'F / 100'C) is not one of those temperatures.
"heat treating" a metal involves bringing it to a high temperature and then cooling the metal at a controlled rate. depending on the metal/alloy/inclusions/pure state/etc/etc/and things way over most peoples' head.... the cooling phases affects how the metal "crystallizes" and how various atoms within the "metal" react. there is zilch comma zero question that "heat treatment" drastically how a metal will perform, and in this case, "as a knife"
should you encounter some company espousing the superior degrees of metallic "....ites" (various apply) - RUN - they're so full of BS you'll never get to anything of "truth"
"tempering" a metal involves bringing the metal to a high enough heat that it "relaxes" and allows any internal built up "stresses" to dissipate. there are a lot of "words" that get associated with "tempering" - annealing / lehring / etc. "engineers" recognize that these are all pseudo-terms for the same physical process / thing.
marketeers otoh depend on the general public being w-o-w-e-d by big words / terminology - basically "if I can't baffle you with brilliance, let me at least befuddle you with bullsh*t."
a "knife" has to be hard enough to take and keep a good edge, and "soft" / "flexible" enough to not snap in half when you use it.
discounting the "BUT WAIT! THERE'S MORE!" 2-3 AM tv hucksters, all those pesky "top name" companies have figured this stuff out.