Umm, they take 30% on that, just guessing but I doubt that "ease" offsets the cost to your earnings
It's par for the course.
If you are used to app dev you are used to the 30% apple takes as well as similar percentages among the various app sales platforms.
Not to mention the up to 55% that international mobile carriers sometimes take to bill on phones. Even still, everyone found that percentage palatable enough because they sold MORE when using that carrier billing solution than if they did it in house with CC's.
I can't say that the Facebook payment system will increase the trust enough to offset the loss in being able to take direct credit card payments, but I'm willing to bet that at least 1 in 4 people will be more likely to pay through them than they would when they see our in house billing system that they may have never used before.
And if they already have paid for Facebook credits when purchasing some other app, and can use those left over credits paying for mine, then I can see a lot of spur of the moment purchases coming from the system. This is something I have learned from split testing and adding paypal and amazon payment options on various products over the last 8 years. People spend more when they already have trust in the payment system.
Keeping things in house does make you more money on each purchase, but you have to look at the extra benefits of working inside of a trusted system, especially when you are already living inside of that platform. Conversions usually change dramatically enough to make it worthwhile.
Here's another example you may be familiar with, when you have an iPhone app with an upsell in the app, what do you think is the best way to sell more: to add a Visa/Mastercard sign to make the upsale or to just add a one click iTunes payment option for it?
Exactly. You know the answer to that.
The same principle can be applied to Facebook.