ECON on only does the following:
Reduces the effectiveness of the AC and Heater but in return uses less power.
Reduces the aggressiveness of the throttle (reduces the rate the car accelerates...if you floor it with econ on vs. econ off..you will notice econ is slowing down acceleration in an attempt to be more power-effective).
ECON Does NOT:
Econ does NOT impact EV vs. HV vs. HV Charging Modes
Econ does NOT reduce the battery power required for driving (although it limits acceleration a bit, so that will save you a tiny bit, but marginal).
Econ does NOT impact the "miles remaining" / "range" values the car displays.
Econ does NOT change the MPG/MPGe rating of the vehicle.
Econ does NOT change regenerative breaking.
Hope this helps.