Customers will only use bitcoins in paying your service or buying your goods when they are already using it. When they are paying you in the cashier and you introduced bitcoin to them, of course they will not grab their phone and do research about it. They would simply say 'no' to you and then carry on to their day. If you're lucky and that customer happened to have a lot of spare time, then maybe the next time he comes to your shop, he already knows about bitcoin and use it as a payment.