We need energy to live:
What we are not use to is to measure energy in physical units for our daily activities. Especially the value of goods is measured mostly using currencies. Unfortunately an amount of #### of some currency unit will not let you survive if it's not convertible into a proper amount of energy.
That's why it would make much more sense to have energy units as a currency in the first place. Most people will understand the value of a kilowatt hour. This is an energy unit that you see on your electricity bill. But it's also useful to calculate other values:
For 1 kilowatt hour you can drive with your 100 kilowatt car (136 horsepower) for 36 seconds ...