Yes, but of course the exchange rate matters as well. It's trivial for Bitcoin payment processors hide an extra "fee" in the exchange rate by giving you a worse exchange rate than you'd get at Bitcoin exchanges and pocketing the difference. (I have no idea if Stripe does that or not)
Inherent to Stripe processing BTC is the fact that you are now a foreign exchange broker. Here's a small sample of why you're going to have to do a lot better than "we only charge 0.5%" to convince me that adding FX risk into my payment processing stack is a good idea:
That cost would be borne by the customer, won't it? I guess that's still in some sense a fee from the Stripe vendor's perspective, because the Bitcoin price will be higher for the customer and thus the quantity demanded will be lower than it would be with the vendor's USD sticker price.
Coinbase does this for free, but they'll take their cut if you try to convert that into dollars. And they don't have a card option as well. This makes it dead simple for anyone to offer Bitcoin while automatically complying with the same reporting regulations as card payments.
Last I checked, Stripe worked on top of the Coinbase API. The main benefit to using Stripe is that's it's one api and one account. For merchants, you also get fiat instead of holding bitcoin (I assume this is what the fee is primarily for). If you're already using Stripe checkout, adding bitcoin can be done in less than 5 lines of code.
Beautiful