I’ve always wished the Macbook’s lowest brightness setting was subdivided two or more times. It’s still too bright when I feel like reading in my dark room perhaps on the way to sleep. I have to use an app called Shady to cover the screen in a dimming overlay.

Have you tried using option-shift-[f1] to subdivide? or the brightness slider in the settings.

Interestingly, on my early 2015 13" MacBook Pro, the very lowest brightness setting seems to have no change in brightness on those last three subdivisions. Once I get down to one full "block" of brightness, option-shift-F1 moves the slider down in quarter-block increments but the screen gets no (perceptibly) dimmer until it shuts off entirely. All the other brightness settings have perceptible changes in brightness at every subdivision level.

Oh my god, thank you!

How does one find these "hidden" features?

Wow, I had no idea that was available.

Unfortunately it doesn't reduce the dimmest level on my MBP. The bottom 4 subdivisions look identical. Like level 0.25, 0.50, 0.75 and 1.00 are all the same brightness, only 1.25+ starts to get brighter.

The lowest level is still too bright at night. That's unfortunate.

However it does reduce the dimmest level of the keyboard illumination!

That's great. I always found the keyboard too bright at its lowest level at night, but some illumination at night would be helpful for obvious reasons. Now I can enjoy 3 subdivisions lower - thank you :-)

After lowering brightness to 0 the brightness can be lowered by lowering the contrast ratio. It’s obviously not perfect but does work.

Most better monitors and everything targeted at office use does not use PWM for backlight brightness control.

LCDs have poor blacks because they're a filter put in front of a lamp, so to render black, they have to try and block as much light as possible, but our visual perception is logarithmic and adaptive, making them look quite bad. The workaround is to add bias light behind the monitor; it quite literally provides a bias for the eye to keep it inside a certain adaption range, which reduces the perceived poorness of dark tones. (It also is more ergonomic.).

The vast majority of modern high-quality monitors have flicker-free backlights without PWM dimming.

https://www.rtings.com/monitor/tests/motion/image-flicker

Yes, there are a bunch of monitors now that do not use PWM for brightness control. And since PWM became known as a problem PWM rate is tested in professional benchmarks. So you definitely can get monitors that do not have that flicker, where the minimal brightness will also not be too high.