Maybe part of it is for the data on WhatsApp users.

* "In the event that WhatsApp is acquired by or merged with a third party entity, we reserve the right to transfer or assign the information we have collected from our users as part of such merger, acquisition, sale, or other change of control." [they go on to say that they may not be able to control use of information in cases which include "reorganization"] http://www.whatsapp.com/legal/

Still seems ridiculously expensive.