They don't have a matching tablet app yet (I keep asking them).
One of the issues may be that I believe the dongle has to have the mic as part of the headset jack. Most tablets just have a headphone jack (no mic), so swiping cards might not work (although I am able to hand-key on my tablet). That would limit the app's capabilities.
When checking out tablets, it might be worth checking to see what type of port it has (headphone or headset).