This seems very inaccurate to me. Most laptops do not have discrete GPUs, so tasks like rendering a youtube video do require CPU cycles. Zoom is very CPU intensive on basically any mac laptop, and people always have a ton of tabs open, which can be fairly CPU intensive.

In other words, there are definitely gains to be had. My ipad pro offers a generally more smooth and satisfying experience with silent and much cooler running CPU versus my MBP, and they offer similar battery life. Scale up to MBP battery size and I suspect we will be seeing a few hours battery life gain.