Practicing on RR cuts and abandoned quarries is legit, but the suggestions for a rank amateur to stroll up to the Barber wall and just go for it is criminal.
Ice tools, be they crampons or hand tools, have incredibly magnified mechanical advantage concentrated on a hardened point. Flakes, crimps, micro-ledges, and other features can all suffer permanent damage.
Is honing your ice skills worth damaging a 3 star rock climb permanently?