confused myself srgb and bit depth

[digitaldog]

If you subscribe that color is a perceptual process in humans, the answers are easy.

If two (different) device values produce results (colors) that one can distinguish when viewed on monitor A, but are indistinguishable when viewed on monitor B: are they different colors?

Two device values and two colors on monitor A. Two device values and one color on monitor B. That's why some purchase 'wide gamut' displays.

If two (different) device values produce results (colors) that can be distinguished by observer X, but cannot be distinguished by observer Y: are they different colors?

Again, it's about perception. The answer is the same as with the display. Device values don't necessarily mean color.

[xpatUSA]

My take is, two different device values are of course different. In the case of the two sRGB values provided, or their conversion to lab (decimal precision as shown by CT), no question they are different values. But with a dE 2000 of 0.01, they appear as the same color! And color being a perceptual property, if the two device values appear the same, they are indeed the same color. This is why I feel it's useful to use the language where appropriate: two device values are two device values, two device values that appear the same are one color.
If we agree color is a perceptual property, if we agree that a dE value less than one, especially the two values under discussion being perceived as one color, well it's one color.
So the two device values are virtually the same but of course different, the color is effectively perceived as the same. One color.

Now that "the same" has been qualified with "appear", "perceived". "virtually" and "effectively", I must of course agree that the two colors will indeed appear the same, be perceived as the same, and look both virtually and effectively the same. This is indeed saying no more than what the literature already says about delta-E and the Just Noticeable Difference.

Therefore, we are both right, eh?