I have a similar device I use on my A4000T IDE header. They are not hot swap though. It treats it like a hard disk is all. You will need to still reboot to have a new card show up.
The best way to go is using rapid road USB on the newer x-surf 100. I have had bad luck with USB and flash drives though. On both my RapidRoad and Spider USB card through the mediator I get a system lockup when moving large batches of files from them to my Amiga internal hard drives on CSPPC SCSI. Also does it if moving to RAM: (I have over 600MB)