Accepting Bitcoin is a sweet deal for merchants and payment processors
Paypal takes around 3% from the merchant. FastSpring takes around 9% (because its UX and features are great, BTW). Meanwhile, Bitpay and Coinbase ask only 1% and bear the risks of volatile exchange rate, lagging exchanges etc.
Zero possibility of chargebacks and near-zero transaction fees are not the only features that make Bitcoin interesting to merchants. Ask yourself: who would pay with Bitcoin today? Those who have some spare cash on a credit card would prefer to spend it first while keeping their precious coins. But if someone pays with Bitcoin, they either don’t have access to credit cards or banking system in their country, or they are trying to avoid financial controls and taxation and thus not trading coins for cash at the exchange. (Person to person exchange for cash is risky and could be 10-20% more expensive.)
This situation allows the payment processor to ask slightly more BTC than the market price (say, extra 3-5%) and call it “insurance against market volatility” (which sounds perfectly fair) and buyers will still be happy to pay it because they either couldn’t pay otherwise, or would have to give up their privacy on exchange. In other words, current situation around Bitcoin allows merchants and payment processors to offload the costs directly on the buyers. This increases adoption of Bitcoin and makes buyers happy: they can now access more products.
In the long term, this 5% markup will go down, but right now it allows the Bitcoin economy to grow and make happy absolutely everyone: buyers (bigger market), merchants (lower costs) and payment processors (higher margin).
PS. I’m not sure how big is the actual markup at Bitpay, Coinbase and others (again, market price is highly volatile). If it turns out to be lower than my imaginary 5%, that’s even better for buyers, but the logic stays the same.