The cryo increases hardness by reducing retained austenite, thus increasing the amount of martensite you have. RA can reduce fine edge stability. So cryo improves this kind of steel by reducing RA, and thus improving fine edge stability, the extra HRC is just gravy. However, to be most effective, the cryo needs to be a part of the quench, not added on later. In fact, I recommend skipping even a snap temper on stainless and going directly into dry ice mixed in acetone or into an LN mist. It should probably soak for a couple hours, though this is an area of some debate.
My experience on the subject of RA and cryo comes from functional experiments I've performed on D2, and from conversations with and experiments with Paul Bos. Otherwise identical blades with the same Rockwell hardness perform dramatically different, depending on the timing of the cryo. By dramatically, I mean one can still shave hair, the other has edge roll visible at arms length.
If you didn't include cryo as part of your quench, I'm sure you'll still have a fine blade, but you may want to re austenitize if you want it to resist roll when sharpened at acute angles. It makes a big difference in D2, it probably does in ATS34.
