I know about the argument against cryo on O1. This is just something that I noticed about it. The dry ice cryo didn't bump the hardness up by any significant degree. 0.1 to 0.2 RC isn't significant as there can be that much error in the conditions of testing it. But I did notice a significant change in how it held an edge. I treat all my O1 to RC 60. They will hold that edge all day, but my O1 filet knife with cryo cutting through bone outlasted even my expectations. It was 1/8" thick and I asked our fishing guide to use it on a charter my son and friends took me on in Florida, It never got dull through two days and over 80 fish and to me that's the best I've ever seen except a D2 filet knife I made my son that hasn't gone through 80 fish yet, but still shaves. The fishing guide bought the blued O1 knife by the way. I explained it will most definitely rust, but the sheath is soaked in linseed oil and melted beeswax, I told him to wipe it down every day with an oiled rag and to still not store in the sheath unless he sprayed oil in it from time to time. Will be going down there this winter, I'll see how the knife is holding up. Had cocobolo handle over a hidden tang. Didn't want an exposed full tang.
Nothing scientific, just anecdotal and those references are not just from people that sell cryo services. The .5% tungsten and chrome would react to cryo as will the .2% Vanadium and vanadium makes harder carbides than tungsten does. It was Hinderliter HT in OKC who told me to do that to O1 and 440C. They were very helpful to me back then and we only ever sent them long paper cutting blades of D2 because they wouldn't fit in our kiln.
Also, this is something I know about first hand. I was told more than once not to treat materials beyond "the book" on account that my company wanted the dies and such to wear out faster. It is a kind of standard in the field. Don't use superior materials or HT because of volume sales, it why some cutters of the same size cost two to three times more as they last as long or longer than that. Changinging out cutters in a cnc takes time.
Case in point I used to have to surface weld a stellite alloy on the end of some steel rods. They would last about a month before the alloy fell off. I drilled some small holes on the ends and then welded the stuff on. I got chewed out for doing that because the parts didn't come back until the Stellite wore down, about 3 months and we had to do them like that all the time afterwards. That was about $1000 a month in business, how much profit I don't know, but they lucked out and received other jobs from the same company because they were impressed because of our "higher standard process" so it worked out.
That may partly be why everybody doesn't do it.