Looking at home and land.. has a small waterfall and a granite plank running beneath property?

Are there any pro's or con's of having a granite plank or monolith run beneath a piece of property with a home. Some of the granite is exposed and there is a small spring away from the home with a small waterfall in the woods. Does this make the property more valuable or more of a solid foundation for a home that was built there. Just curious as the sellers seem to be pushing this feature on the property...