Office for Mac 2008 Installer will install both sets of code (Intel/PPC) regardless of what machine type you are installing onto. This is common behavior for the Apple installer and is important in the cases where you are installing onto a drive that might be shared with Intel/PPC computers (such as an external travel drive, Network Boot servers, and Shared Network Application Folders).
According to developer Matt Centurión:
I'd like to tell you that it is ok to use utilities like "Trim The Fat" to remove the code that doesn't map to your processor, however I fear that doing so might complicate upgrades and patches released for Office 2008 in the future.These patches and upgrades will expect the full application and sets of code to be there in order to run and if not, you will be unable to apply them. This might also be true for other non-Microsoft applications that make use of the Apple installer.

Comments (1)
Posted on February 4, 2008 06:48
John Lockwood:As far as I am concerned this is a good thing, it is supposed to be a Universal Binary after-all, besides these days disk space is cheap.
Adobe on the other hand are very confused. Acrobat Pro is a Universal Binary but Acrobat Reader is EITHER a PPC, or a Intel (not a Universal Binary). As a result I cannot make a Universal disk containing Acrobat Reader.
Posted by John Lockwood | February 4, 2008 6:48 AM