It IS dumb. But it looks nice. Black vinyl is better for quality in my opinion. But I have to admit that looking at a record spinning round is part of the pleasure of playing records. So looks are important, otherwise we'd all just play digital files all the time (some do, of course). And artificial scarcity gives something a sense of value - and it does in reality give it value, once you see the prices people are willing to pay for the limited version on Discogs.
One thing I've been thinking of is putting out our releases in limited black vinyl, slightly cheaper than the rest of the run, which will be coloured.