I just updated to the latest version and checked out the new "secret" Palantir, and I noticed the message you get when you click it:
You ponder the orb for a while, but do not yet know how to make use of it.
Note the "yet" in the message, implying that you will be able to use it at some point! I'm thinking it will probably be linked to alignment (Probably with mordor/high elves). Regarding what it will actually be used for, I don't know. Maybe it will be used for smaller-scale map viewing (Think Journeymap) aas well as interconnecting all palantirs in a world.