I see your point. However, I've found that many domainers judge their domains in isolation, as if the rest of the market weren't out there. You'd be amazed how many 3rd-tier domains are priced above their 2nd-tier or 1st-tier counterparts.
It's important to know not just about your domains but about the status of preferable alternatives.
If I'm appraising your condo, it's DEFINITELY worth mentioning your neighbor's condo if it's in better condition and has a nicer view and is either for sale or has sold recently.
That's my logic here.