I often move files from a destination to another and sometime it has happened some faulty hard drive with bad sector. It would be really useful if I can replicate on two or more destinations at the same time, so if I have a problem of any kind my files are on the second destination.
It's for those situation when you want to move the files without reading them twice, not a full backup need. New drive expecially, have failed during the first days when I transfer the files from an old, failing too, drive. So, multiple copies with one read is what you need to minimize the risk.