We have had 15 years of World spintop contests, but they were ad-hoc without any entity giving them a stamp of approval. The yo-yoers now have their own international federation and although they are willing to host us one more year in Japan (if we decide to go), we are not part of their charter.
As a concrete example of why it would be good to have a federation recognized by an international entity, Enrique Leal had talks last month with the Colombian government agency in charge of promoting sports. They gave him a list of international institutions, saying that if we were affiliated with any of them they would sponsor a world contest in Colombia, providing the logistics and significant funding. The list includes the International Olympic Committee and such, but when I checked all the sports recognized, there were many things like Tug of War. I think we have at least as big a claim to be a sport as Tug of War.
In addition to organizing and validating the contests, as Jim says, an association will help in the exchange of knowledge between different spintop cultures around the world. Although the community that plays with tops in our acrobatic or juggling style is very small, there are millions of people who play in some fashion with spinning tops. Our goal is to promote all variations of top play.