It's not as big an issue as it once was as most lighting has been modernized to technologies which aren't directly related to a power grid's freqyency. LED's almost all fonction on PWM for regulation, and there's no standard rate for that. Plus it's a lot higher frequency. If you watch driving vids from anywhere, you'll see some cars brake and taillights pulsing which is because their frequency is a multiple of the 50Hz or 60 Hz selected on the cam, and whichever one you select that will happen anyway because all cars are different with this. I've had cams where I forgot to check this setting and didn't notice anything in the vids I watched, only discovering it later when playing around with other cam settings. Sometimes it makes a difference and sometimes not so much, same as with any cam setting, which is why it's best to try the different settings to find what works best for you.
Phil