Earlier quoted context omitted.
Primary reason it turns off is because its oled, and leaving it on would cause burn-in.
Sounds like a great application for an e-ink display. No burn-in, low power, and can always emit as much light as the keys on the keyboard do (by front-illuminating the bar when the keyboard backlight is on).
...that’s why Apple’s adoption of it surprised me the most: I saw how it on the ThinkPad added no value, and while Apple has greater integration and will undoubtedly encourage third-party devs to use it - it will still be too fiddly and complicated.
I think Apple’s too proud to kill it off in just one project cycle - but I can’t see Apple’s management justifying continued investment of time into maintaining it. The fact they didn’t include it in their latest desktop keyboard (for a Pro users no-less!) says something.