Well, because they're absolutely delicious, that's why!! My partner and I call them "grape grape grape grape" because they have such an intense sweet grape flavor. Each year we gleefully wait for them to come into season, and I'm surprised we manage to bring some home - we end up gobbling them right from the bag on the way home.
Kyoho grapes were first developed in Japan and are a cross between Campbell and Centennial grape varieties. They have a Concord-like sweetness and their skins are loose - this is known as "slip-skin." The fruits are larger than most grapes, making your mouth explode with sugary goodness.
(Image: Kathryn Hill)