The much awaited Microsoft Office app has finally come to the iPhone but with caveats. Users need to have an Office 365 account in order to use it, and there's no version for Apple's iPad, which is the mobile device that would most benefit from having MS Office running natively.
The reason for this could be that Microsoft Office is the key differentiator of Microsoft's Surface RT tablet which is an iPad competitor and which has the only version of MS Office on any mobile tablet. Giving the iPad a version of MS Office would instanly bring it one step closer to its post-PC aspirations but that might mean even less Surface RT sales for Microsoft.