Very interesting. I wonder if this would be easier to use than SCSI2SD[0].

SCSI2SD reportedly works well with older SCSI computers (old Macs in particular), but it requires very careful formatting/setup of the SD card you're using.

[0] http://www.codesrc.com/mediawiki/index.php?title=SCSI2SD

Yes. I'm using one with a Kurzweil K2600 synthesizer. Really, for most devices the only reason it requires care when setting up is because the usability of the config software is poor, and the documentation is worse. For a simple case (like just turning the whole of a 4GB SD card into a single virtual disk it's pretty straightforward, once you understand what the config utility is expecting you to do.

The docs say that the hardware supports both initiator (host) and target (disk/peripheral) modes, which could open up some older hardware devices as well.

Maybe also SCSI printers, scanners, CD-ROM, etc. Sounds like everything could be emulated with this.