Many of your potential Bitcoin customers aren't going to be shopping with you if you don't accept Bitcoin. So you don't "save 16 cents." You gained a sale where you previously didn't have one.
I have acknowledged that there is a good reason to take bit coin, and thats to get customers who would not have known about us... but thats a separate argument then if bit coin will save me money over traditional currencies.
A lot of people here just assume its the best thing to do in all cases, and anyone who is not accepting bit coin is an idiot.
My goal here is to play devils advocate, by addressing your solutions with real world examples of why it might not work. Simply saying "its cheaper then credit cards or paypal" is not a good argument for why my business should accept bitcoin. As I have shown, using bit-pay, it would take years to just break even on the investment to get it setup. Your asking me to invest money in something that after years ill get back to where I started. If bit-pay develops the plugin for my cart, then of course I would implement it, even if it costs the same (or slightly more), because if no one uses it, I have lost nothing, and if everyone uses it, I will get new customers.
For me, the more compelling argument is the marketing aspect of accepting bit-coin. Being an early adopter in this market means that my business will really stand out. Also technical people like to support the thing they are passionate about. If a sizable portion of bitcoin pioneers like tea (in my case) then it makes since to put my products infront of them. But its a risk... I know I wont make my money back on the savings of credit card fees, so I have to take a gamble that enough of you all want to buy my product that it would work out at the end....
Its far from a no-brainer!