Because odds are you won't be able to use a Happy Card to buy a different gift card. I was shown a memo from Home Depot telling managers not to permit Happy Guy cards from being used to buy Home Depot cards (or any other gift cards sold at Home Depot, including Visa prepaid gift cards).
Well, if the self-ck method works, they will never know. Even at reg ckout, fairly easy to face the stripe side toward the cashier until you swipe, and simply extend your hand.
You can get away with doing that sort of thing now and then, but it's nothing you should count on being able to do.
Who claimed one could? Also, as I mentioned, I can't even attempt it as my grocer doesn't sell the 'GUY' version.