Suppose you're poor. You do not have the money to support yourself 2 months. You call the helpdesk for cox, they come and repair your cable modem, but somehow they "blame" the problem on you, and that's $250 for riding out thank you very much.
Now let's assess what happens in 3 situations : 1) you have a bank account - the money's gone the moment they say you spent it with them - you have no recourse - you call them - they've got everything they want, you have zero negotiating position - even if you achieve the impossible and talk them out of it, the money's gone for 2+ months 2) you pay by credit card (obviously only available to "the rich", granted, not quite "the 1%", but I'm pretty sure >20% of Americans effectively don't have access to a credit card) - the money's gone the moment they charge you - you call them up, ask what's going on, they don't cooperate - you threaten them with a chargeback - they will suddenly become very cooperative 3) you don't have a back account (with positive balance) - their payment request bounces - they have no recourse - they call you and ask if there's anything they can do - they're pretty cooperative
The "mystery" of why poor people, students, ... go with option 3 is not much of a mystery to me. It's because option 2 is not available to them.
The same goes for being a customer of any service firm. Internet, telephone, car insurance, ...
Pretty much every developed country has spoken in the last few years of forcing depositors to take losses in the event of bank failures, and some have actually done it. Governmental deposit insurance SHOULD be inviolate, but that isn't the way the regulators are talking and acting.
Meanwhile, how many HNers are currently praying that Mt. Gox will stay liquid long enough to give them back their money?