I remember reviews on youtube that showed the macbook air/pro M1 playing video (streaming?) for that long. Actually, it kept going for 20h.
The question is, what's the battery life when you're doing kernel compiles or GPGPU.
And not to beat the already long dead horse any more, but toss in some electron apps running in the background, I probably average somewhere around ~7 hours or so. I'm not convinced the 10+ hour lifetime is possible if you've got stuff like Discord/Slack/VS Code open.
But in terms of when I am doing truly evil things to it, I am surprised it lasts as long as it does, be it max CPU compiling or all of this morning when I was toying around with stable diffusion, it gets around ~4 hours or so.