I think KDE has some dependency on Marble functionality, that's why you can't easily get rid of this application in many KDE-based distributions.
On the other hand, this is really useful tool when you talk about education, like Edubuntu or OpenSuSE Li-f-e.
http://linuxblog.darkduck.com/2012/08/edubuntu-1204-lets-learn-it.htmlhttp://linuxblog.darkduck.com/2012/09/opensuse-12-1-li-f-e.html