This could be used for Hot Drinks Vending Machines maybe starbucks could try this.... The temperature increase is obtained by direct absorption of microwave radiation by the liquid to be heated
meaning no disrespect but it seems you are confusing effectiveness with efficiency, and cost savings is a function of efficiency your example is getting at the convenience factor of speed, given the heating environment specified, but is not looking at energy in as electricity divided into energy out as heat in water (efficiency)