Looks like the downside would be that the capacity of your 16 GB usb drive would be reduced to a single floppy (i.e. one floppy per usb drive) ?
Yes that is a downside.
I think it would be useful on a big box Amiga as a DF1: for transferring between Amiga & PC etc.. Though not the best option as you could always use IDE to CF adapters.
Hmmm... There must be some sort of use for it.