Distance from the coil is critical, plus, the coil does get quite hot. The consistency in position and the ability to consistently drop the cartridge from the coil gap. Any induction annealing is better than any flame annealing, but the automated feeder does improve the process.
Nothing wrong at all with the Annie, and with the Giraud feeder, a guy has options - go induction or go gas flame. I just wanted a little more speed in set up and the precision/adaptability of the Aztec mode to perfect my cycle time. Using a case feeder and the amp mate on an AMP, a guy can dump cases in the feeder and walk away. The Giraud feeder has to have cases oriented in the hopper. Not a big deal, but it’s a difference.