Would have thought, from the description, as if few would find a requirement for one. It seems you need a group of people all wanting to use the WiFi at the same time, wanting to run it from one person's mobile data connection. Fine if you need it, but I can't see me likely to be in that position.
Thinking about it I have been at work when someone set their mobile to generate a WiFi for the rest of us anyway, without the need for a "dongle" as far as I can recall.