Why are Watt's more common than VA's?
Watts can be used to power your kettle, run your TV, refrigerator and power your hi-fi. You get billed for watts. However, some appliances will take more than just watts - they'll take reactive power (VAr) and although this doesn't contribute to lighting a lightbulb or actually turning a fan, this reactive power is taken all the same.

This means that the electricity company have a small dilemma - the current that flows thru their cables to you house is bigger than the actual current needed to do work via your appliance and this is a dilemma because the wires have to be thicker to take that extra current.

So, in some case your utility company will make charges (to certain customers) based on their watt-hour usage and their reactive watt-hour usage.

Luckily, most househoold customers only get billed for watt-hours used.