If I understand correctly, you claimed WS-15 increase power is for electrical power not for kinematic improvement.
To me it sounds like a priority choice not high school physics thus the source.
You understood incorrectly. Let's parse the sentence together
One of the interesting considerations
This means that there are several interesting things for us to consider about the WS-15, what follows is one of them.
isn't so much the kinematic improvement from the increased power
While the kinematic improvement is an obvious and welcome benefit from the increased power of the engine relative to the WS-10C, this isn't what
we will consider here.
meaning increased electrical power to run more capable and power-intensive electronics
The increased power is useful for many things, but here we emphasize that it is useful to run more capable electronics that require more electricity.
To give a broader context for my observation, Blitzo brought up that the WS-15 is more of a lux upgrade (my phrase) to the J-20 since the WS-10C is already quite powerful and while more agility and better supercruise is welcome, it's not as decisive in modern air combat as better electronics (better sensors, better datalinks, MUMT, "intelligentization", etc.) I wanted to bring up a counterpoint that a more powerful engine allows better electronics, so the WS-15 is useful even in that regard.
