Good point. The bench players now don't matter since they're ever changing because of injury, Conrad and Maysonet are one call away.
The speculation I read last night is maybe they're just trying to cover their bases with Hart because they don't want to push him too hard right away, and Ishikawa can play a little OF as well as 1B in case they need someone extra.
I haven't heard anything about Jay Gibbons, but he's pretty much option number 4 after Schafer, Gindl, and Patterson anyway.