CC fees ain't 5% mang.
1-2% at worst. Standard wholesale is 1.54%, may go to 2 when accounting for fraud-related expanses.
Maay be 3% or so for things like paypal or cross-country, but i doubt extra-large companies have trouble negotiating down to 1.5% or so, and they certainly don't need to use third-party shitty conversion rates.
Digital stores taking 30% is pretty interesting. It basically means a copy sold through your website \ store is +50% revenue against a third party store (0.7 * 1.5 = 1.05)