Because purple is an awfully great color.
I've become a big fan of using decks that catch a marks attention and help cover my poorly executed sleights of hand. This bright purple deck of Riderback 808s also includes a double backed card, a blank faced and a totally blank card.
Purple is lots of fun, but this Black Ghost deck is pretty dramatic.
Bicycle Rider Back The Purple Deck with Gaff Cards for Magic via Amazon