Yeah it's nothing special, you are correct about the trendy thing. Purple bud just tends to be more appealing to the eye, especially for newer smokers. I tend to look for trichrome formation, but added purple dosen't hurt.. Some growers specialize in purple weed, for whatever their reason.. All I care about is crystals on the bud, color isn't too big of a deal. I've gotten some killer brown weed, one time before.. Take it easy!

--SS.