Aside from the Heroes, the only uses I could see are allowing you to build some of the more modern Oceanian or American cultures that have other cultures as prerequisites, and allowing you to build one of the few culture-requirement wonders. I wasn't really thinking of that as the primary benefit anyway, just as a small side effect that maybe fits the theme. In the same vein but easier to implement, maybe have it create a random Culture(<continent>) in its city.
Providing cultures that you don't have yet is Ellis Island's job. I'm waiting on a separate XML tag to allow a building to produce more than one free building in cities.