Earlier quoted context omitted.
Why do you believe that?
Specific to the electric plane, you remove some of the battery weight, as that energy would then come from the catapult. But, as a general thing? I don't see it happening. There's a TON of complexity in a catapult system. Plus, the amount of spilled champagne in first class is going to ruin a lot of suits and blouses. Can't have that. ;)
But it's all on the ground.