Natural gas is consumer priced in GJ and seems to work fine. Eventually we would just develop and intuition about number of K/M/G J in various battery sizes without the complex/ugly kwh unit.

It basically comes down to stating things in their simplest and most correct form. It is like using 75/25 to express the number 3. When expressing an energy value, use the right unit (Joule) not a derived unit multiplied by another quantity to get back to the original.