Maybe we should wait and see how the app actually works on the iPad before making assumptions like this. You can already import photos and video from the iPhone (or another camera) to the iPad with the camera connection kit, so perhaps iMovie will support adding compatible videos shot on other devices.
Sorry, that's not correct. According to Apple's website:
Share among devices.
Want to shoot with an iPhone and edit on an iPad? No problem. You can transfer your iMovie projects between compatible iOS devices via iTunes.
So you're sitting somewhere reading a book. All of a sudden your kids do something adorable. Or you brought it with you to amuse yourself while the family drives someplace. Then you see something wonderful. Or you never thought you would care about taking videos, certainly not enough to spend $100 on a video camera, but it's already built into the iPad. Turns out it's really kind of fun.I guess I'm having hard time seeing why someone would carry the iPad around to shoot video.