Ok imagine next time you buy flights or concert tickets, instead of invariably paying some $6 credit card surcharge per booking, you are offered the option of booking with bitcoin for a $2 or even no surcharge. I will definately at that stage start looking at paying with bitcoin.

Then as a significant proportion of the population (say 20%) starts paying with bitcoin, other online shops like amazon will start seeing that they are saving a LOT by not paying 2% interchange fees to cover bullshit credit card reward programs and fees. And then the number of stores charging an additional credit card levy will increase as shops are not automatically building the credit card fee into the price, and then the number of people being pushed into bitcoin will increase.

The only thing that can stop this is credit card companies effectively lobbying that shops cannot charge more for credit card payments. this has happened historically in some juristictions, but is really pretty hard to justify for any sane reason so will be unlikely to stick.

This will either really marginalise credit card companies significantly, or really force them to put the screws on their interchange fees (and greatly reduce their rewards programs).