Though it was less than a year ago, how I discovered NiZn batteries is lost to the mists of time. Their 1.6V rating makes them useful in some situations, and a wayward AA cell provides another excuse to play with scope math.
I do remember why I was searching, however. My DSLR camera was not working well with my various NiMH AA cells--it never had, but had become even worse. Surely all the cells couldn't have gone bad. My assumption, borne out by some web searching, was that the camera's battery sense threshold was a bit too high. Maybe it was in my search that I stumbled across mention of this new (actually, not so new) chemistry--newly available at least--Nickel Zinc, with a 1.6V cell voltage. That seemed a good candidate to make my camera happy.