Why keep the package?

Why does the install package remain on the U3 device? I would like to use U3 OpenOffice. But it's kinda annoying when after install the drive's down a 230MB capacity. This could easily be reduced to 160MB just by deleting the 70MB install package. Yes I have tried deleting it. Deleting the package renders the application unusable... Very annoying indeed. I think I'll just try the Portable Package instead, and try to make an icon with the software I just found here. Would be nice though if you could make it so that the U3 version deleted the install package itself without the need for it afterwards on insertion.