From the app player's point of view, so far as I'm aware the only way to donate vast numbers of FP at once is to sit around painstakingly loading them up onto your FP bar 10FP by 10FP beforehand. While you're doing that, other people can be donating (and you can't see them doing it). If someone else turns out to have topped the building off already by the time you've preloaded hundreds of FP, then you've got no means of getting them back into inventory again - they have to be dumped somewhere else.
So it doesn't seem to me like much of an advantage...