I guess it does print money...
Nintendo's recently released StreetPass games have made about $4 million dollars in their first month, according to Satoru Iwata in a recent interview with with Tokyo Keizai Online.
This is shortly after news that the games were selling very well. The paid additions to the StreetPass Plaza include four new games, and can be purchased individually for $5 each or as a bundle for $15. Hopefully this success will lead to more StreetPass games, as well as similar piecemeal experiences from Nintendo.