Imagine this. You're former executive with Morgan Stanley (lets say for arguments' sake, you were the vice president of mergers and acquisitions).
You are no longer with the company, but need to get rid of the BlackBerry you had been using.
Sell it on eBay right? Sure why not!
But before you do you'll wipe all sensitive data off the device right? Wipe it clean so that the new user can start fresh?