1. Power Factor basically indicates the quality of power. If the power factor is 0 you can’t gain any useful mechanical work, though the kVAh Metering will keep showing energy computation. However, incase PF is 1, it will give maximum work output.
2. A motor output will directly depends on input PF. Hence, a low PF input would consume higher kVAh input for the same work-output and consume more energy.