well, another factor is that Miami has both Ricky Williams and Ronnie Brown.
It is a method to get their most talented players on the field at the same time in a useful way.
I think the league has figured it out and it'll go away soon. Excepting one drive when the Fins were using more of a spread option running attack than the wildcat and scored a TD, they are averaging something like 1.5 yards per attempt with the wildcat over the last three or four games. Won't cut it in the NFL.