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you dont throw someone that has never swam before, into the deep end and tell him its in his best interest to hold his breath.
instead you find the easiest way just to get him to try it, even if he aint going to use the pool ever again. atleast letting him get his toes wet he will see how easy it is to say "yes customer heres a QR code". once they have got their toes wet, then you introduce them to the art of swimming, diving in head first, or somersaulting into the deep end (investing).
another analogy
dont throw 5 eggs at him at once or he will just defend himself and the eggs will just hurt him and break. instead gently hand him one egg and and then a second egg.
I'm sure if you ask most merchants who accept BTC most of them are unaware how easy it is for them to accept payments directly without a payment processor and also unaware of the benefits of doing so. This is my experience anyway.
And how much more difficult is it to integrate a wallet rather than an API? In reality not a whole lot.
Why don't we focus our energy on making it easier for merchants to accept bitcoin directly rather than preaching to them to use BitPay/Coinbase?
All we need is for Coinbase/Bitpay to get hacked or run away with the coins and it's game over, most of these merchants will never touch bitcoin again. And lets not forget that fairly serious issues were found in the coinbase website during the last vulnerability bounty programme. If this keeps up it'll end badly. It's already showing signs of bad things ahead with the recent Coinbase AML requirements. Coinbase IS the PayPal of bitcoin currently and there should not be a PayPal of bitcoin as bitcoin makes PayPal obsolete.