OK, well, first disclosure: I have no idea how much demand there is, nor how well this device works, from any personal experience, so keep that in mind when reading everything that follows
I think the device would have a use for anyone who has 35mm slides that they would like to have in digital format. The resolution is not super high, but good enough for most online viewing. I don't know how many people have a need for that, and want to do it themselves rather than send off for it.
Additionally, it looks like it uses a SCSI interface, which is pretty much non-existent these days, so some kind of adapter would be needed. I did a quick search and it seems they are available and not expensive, so that shouldn't be a show-stopper, but people would have to know it's needed and that it's available.
Maybe just monitor the auctions you see on ebay and see how quickly they sell, and for what, to get a feel for the demand for it.
I didn't get into photography before digital, so I have no slides or negatives to scan, which limits my expertise on this, but there may be others who have a ton of stuff that they'd like scanned.