Yet the service into my home and each individual circuit has a maximum on received power so the Watt is usually more pertinent anyways. Taking an average Watt usage value and extrapolating that into kWh/month is both incredibly easy and completely standardized.
0.108 x 168 hours/wk x 4.4 wks/month gives a good approximation for kwh/month. Demand over time gives consumption just fine.