This discussion is about other areas where flicker might have an impact.
I can confirm that certain studio monitors/loudspeakers have flickering user facing LEDs used to indicate power on and various operational states of the device. However, the flicker is at several thousand hertz. For example the Genelec speakers. Some models allow you to turn the LED off. This is relevant if you have such devices facing you for hours at a time typically also next to a flickering workstation monitor. Their are other pro audio equipment with PWM screens like audio interfaces, etc.
Then you have the RGB "mood" lighting or audio visualizers of consumer and gamer oriented products including PC component lighting (motherboards, fans, cpu coolers, memory), many of which use PWM.
Certain traditional wrist watches with digital displays (not smartwatches) have flicker:
https://www.watchuseek.com/threads/what-is-the-lcd-flickering-when-you-tilt-a-watch-at-an-angle.293381/
The reason is that the LCD segments are not on all the time, they are constantly being pulsed on and off (refreshed) with AC power because DC power (i.e. constantly powering on LCD segments) will lead to permanent polarisation of the segments and reduce the life of the display. The refresh rate is fast enough so as not to be noticed by humans, like on a TV.
The refresh rate on solar-battery models appears a little slower than on non-solar battery models, probably an attempt to reduce power consumption further.
The digits are not switched on 100% but they are "multiplexed"
So the watch will first enable digit 1 and switch on its dots, then it will enable digit 2 and switch on the dots while digit one is loosing power and fade out.... until the last digit is set.
And then begin with digit 1 again.
That reduces the amount of dots switched on in parallel and so the power consumption.
Both, the human eye and the LCD are somewhat slow switching.
In dark areas the flickering contrast of the LCD will not be visible.
In very bright sunlight you can see the small amounts of contrast changes in some viewing angles when contrast goes weaker anyhow.