simple. It charges faster with more amps. If I'm at the track and my radio is running low on charge, I know I can throw my cells on the charger for about an hour and easily get through the rest of my day. Sure, maybe 1.2 amps might hurt the batteries more in the long run than a charge rate of .5 amps, but these cells are so cheap that it doesn't matter. Plus, it doesn't seem to hurt them at this rate to the point that they vent or drastically lose run time. I'd imagine they could probably take a higher rate than 1.2 but then we might start seeing a loss of runtime which is the more important factor in your radio as opposed to wanting more voltage.