I'm regularly amused by members who do no comprehend Praxeology or Economics telling me how consumers should act.
Since you're obviously an expert in both, what do you think will motivate a consumer to use an irreversible method like Bitcoins to buy something online instead of their Visa card?
Reversibility comes at a cost. A reversible transaction is essentially an insured irreversible transaction.
Insurance isn't free, you know? Some people would rather not pay insurance because they trust the merchant. With your Visa card, you are forced to purchase this insurance and you are forced to bail out people who use their visa card irresponsibly.
Real life example: The shop where I buy electronics is a "bare-bones" merchant. Very limited customer service, very low margins, and so on. That's why they can afford to charge 10-20% less than the high street merchants. The also charge 3% extra for credit card transactions as compared to cash-in-hand because that is how much it costs them, and it's the type of shop that likes to pass the savings to the customer.
Some low-cost airlines do the same thing.
Just because most merchants effectively subsidize credit card customers, don't assume that all of them do and don't assume that some customers don't want that choice.