That was fun, thanks! I scored a perfect 0 but I admit that I had to stare quite hard. Some of the purple squares were not "plainly, obviously different".

But the real issue here is surely simpler. To me, when I buy a screen (or whatever), I know in advance that (A) I will not be comparing it daily with another screen, and (B) it will be - easily - good enough for my purposes.

You might say I'm depending on other, more perfectionist, consumers to do the quality control. Fair enough.