How did you do that?

On Samsung devices, there's is an option under the Accessibility menu. Then go to something like "Improve Display" (mine is in Hebrew, so that is a rough translation that might not be exact) and then "Customize Colours" (again, rough translation).

Additionally, I believe that there exists an additional method to enable greyscale in Developer Options if you have that enabled.

Yeah I don’t disagree. But on the whole I think it gets you a long way towards it without the cons of having two devices for example.

Alright, I just spent the entire day on greyscale yesterday to check.

I think that I suffered more eyestrain than usual, mostly because I could not tell icons and other UI elements apart. Yet I don't have this issue on the E-Ink device, interestingly, even though I use many of the same apps e.g. Telegram.

I would say that the difference is due to the reflective vs radiative screen, not the greyscale palette.

Maybe it's a mismatch in requirements. For me, I move it into greyscale to give my monkey brain less reason to want to play with it. The intention when it's enabled is that if I need to set a timer or jot down a note that I don't get sucked into the device. When I'm done in a deep work mode, I switch it back to normal screen.

So for me, the whole point is I won't be using it enough to notice eye strain or something like that. If I'm messaging or doing something the device is designed for, it's a benefit for me to be able to have it in full fidelity.