South should have visions of slam when the auction starts 1♦--1♠; 2NT rebid by North to show 18-19 points. Now South should know there is a great source of tricks because of the terrific diamond position and will go for slam. The grand depends on finding West with the ♠Q: not worth the risk to bid, but we'll enjoy the overtrick.
Benefits include:
Plus... it's free!