You can fit the same energy in a smaller package, sure, but the...

You can fit the same energy in a smaller package, sure, but the motor still needs a particular amount of energy to move the vehicle say 400kms. I don't think you can short-change the motor and expect it to take you as far! At the end of the day, the motor still needs a certain amount of kWh per km (affected by weight etc, but you get the point).
Smaller and lighter batteries are certainly a huge benefit though!
Where are our resident sparkies?!