Because we've evolved a hell of a lot of ways for people to offload responsibility over the last hundred or so years, particularly where money is involved.
Sure, the bank/CC company will take responsibility for fraudulent charges. In return, they:
1. Randomly cancel your cards and mail you new ones to limit their risk. (No explanation other than 'security')
2. Refuse to let you use your cards to deposit on gambling sites (which are legal in Canada). They also charge extra fees for 'cash-like' transactions on things like forex sites.
3. Reject large purchases that are 'out of the ordinary' making you look like a jackass. This one happened to my dad while he was booking flights.
4. Skim 2-3% or more of each transaction.
5. Maintain onerous requirements for merchants. Square has helped a lot with this in the first world but in the rest of the world they don't even bother taking electronic payments because it's such a hassle to get approved, lease the machines, maintain a security deposit, etc.
Sometimes it makes more sense to just take the risk of getting scammed than deal with all of the above.
So what happened when credit cards went toe-to-toe with bitcoin? Bitcoin got its ass handed to it. http://pando.com/2013/08/27/an-expensive-lesson-against-sell... Ebay had to ban bitcoin sales because sellers were getting ripped off so often by credit card owners.
How so? The whole scam was predicated on abusing the chargeback feature of credit cards. This just proves that credit cards are terrible at cash-like transactions (buying cash/gold/bitcoins/gambling).
