The diskspare.device was acceptance replacement when I tried it on my Amiga in mid 90s however it was unstable on certain cheap and old disks. Since diskspare.device had to be loaded before it could be used it was usable only on HD systems. But when you have HD why use floppies?
IIRC when I only had 30MB harddisk on my A600 I used diskspare.device to store some lesser utilities to floppies. I was always short on disks so I wanted to cram more stuff.