I don't know anything about these or why I would want one though.
I understand as I did receive a few emails with questions regarding the unit. In a previous article (the DV4mini review) I did explained in the introduction the purposed of a digital hotspot. Maybe I should have used is again. You can find the complete article on my personal website in the publication page. Below you will find part the introduction text of this review. Hope this help.
"More and more modulation protocols from different vendors are now available for the ham community, including D-STAR, DMR, and C4FM (Yaesu’s System Fusion). In the ham digital world, a reflector is a server connected to the Internet that acts as a virtual repeater. Digital hotspots provide the ability for amateurs to connect to those Internet reflectors from their digital transceivers. Hotspots contain a low-power transmitter and receiver for amateur frequencies, and plug into a computer connected to the Internet. "
You can have repeaters, stations and hotspots connected to the same reflector via the Internet or Hamnet (private Internet for hams). Let say you're in Florida and you have an OpenSPOT, you can connect to reflectors around the world and be broadcast on repeaters network as you were local. Please note that you need a different radio on each mode, except for cross mode in DMR and C4FM demonstrated in this video.
73 Pascal VA2PV