The article says Lithium Ion batteries deliver 1/15 the power per pound of traditional aviation fuel. That leaves a lot of room for improvement...
They're optimized for energy efficiency? Yes? What does this gotcha response even mean?
For plane designed from ground up as electric fact that jets land lighter than take off is not relevant.
It is only relevant if you want to retrofit electric engine on jet engine optimized chassis - which is not only possible way.
Bit more info on how thought process goes: https://spectrum.ieee.org/aerospace/aviation/how-i-designed-...
These are constraints that can be designed around, and you have more freedom to do so when designing from scratch, but doing so is not a optimization, it is a straightforward trade-off between weight and duration. There's no optimal hump on that line.