Re: Reverse Channel Cannibalism 5GB on a cellphone is a lot. (esp. if no streaming video has been used.) But for a full computer -- laptop, desktop, etc. -- there can be 5GB of background traffic invisible to the user.
If you have internet access at home, work, friends' houses, numerous resturants, etc., then there's very little need for a MiFi. If you have a cellphone with data, then there's almost zero reason to have one. I got one simply because it's "free" (minus "deposit".) Being anchored to Clear's WiMax network means it's coverage is laughablly small. (I'm surprised it stayed connected from RDU to West of Apex, NC on US-64.)