Those merchants who spam B>Scrolls, practical to sell to?

I've always seen them around for years, but I've never believed they would ever make money consistently, they offer so low and stick to it. I always imagined that the only buyers they ever got was new players who didn't know the value of anything. And there's only so many of them.

but now, playing MS again, I have to wonder: Is there ever a condition/situation when a knowledgable player would actually agree to sell low to these stingy merchants?