I get about 14-16 hours out of my M1 MacBook Air doing basically full-time development (browser, mail client, Slack, text editor & terminal open, and compiling code periodically).

I know everyone's use case is different, but most of my development workload is 65% typing code into a text editor and 35% running it. I'm not continually pegging the CPU, just intermittently, in which case the existence of low power cores help a lot. The supposed javascript acceleration in the M1 has seemed to really speed up my workloads too.

Might be less computationally expensive. But video playback constantly refreshes screen which uses up battery

Did Electron fix the 60Hz (or rather current screen refresh rate) cursor blinking? Otherwise I don't see many web devs getting a lot of runtime in.

That's actually a curious question, I wonder what the most energy efficient dev tool is. Can't imagine its VScode. Maybe plain terminal with VIM?

This is true, but it's not worst case by far. Most video is 24 or 30 fps, so about half the typical 60 hz refresh rate. Still a nice optimization path for video. I'm not sure what effect typing in an editor will have on screen refresh, but if the Electron issue is any indication, it's probably complicated.