That is a valid point. I personally offset that $400 with rebates. The remaining amount is totally worth it to me to have chargeback ability, extended warranties, insurance on my rental cars, and all the other perks you can get from credit cards. Having to visit ATMs and be responsible for actual cash is a (small) burden that I'm happy to be rid of.

On the merchant end of things, accepting card payments reduces their exposure to risk from theft (both internal and gun-in-your face type). For the big guys, the fee is in the low 1%.

But you're right about the lack of transparency. If card fees were required to be itemized separately, the whole dynamic would shift dramatically. But as far as Apple Pay and similar systems are concerned, the 0.15% is bitten off the banks' fee already, and the price of the transaction isn't based on cost, but on value. As a thought experiment, imagine if Apple stopped taking a 30% cut of app store purchases. Do you think that $0.99 games would be priced at $0.69? Probably not. I think the same is probably true of merchant fees--that they're not going to--on average-- increase by 0.15%.

We'll know for sure in the next several years though.