Mark Straub wrote:They were originally invented for chopping steps, something made mostly outdated with the invention of crampons
Mark, various posts in the thread have summarized uses and dangers of adzes. I'll just comment on the history a bit. Cutting steps remained popular long after crampons were invented--even 12-point crampons. The first 12-point crampons were made by Laurent Grivel in 1929. They were used for the first ascent of the Eiger Nordwand. Yet, when in 1968 Flematti and Desmaison climbed the Linceul on the Grandes Jorasses, they still cut thousands of steps in the ice. When Messner wrote of his solo ascent of the North Face of the Droites in 1969, he felt the need to explain why he didn't cut steps. Incidentally, he carried an axe and a dagger, which was not unusual at the time. The late sixties and early seventies saw the development of "piolet traction" which required not only front points but two (short) tools. Only then the decline of the adze begun, some forty years after the invention of the 12-point crampons.