it is not really new to see this kind  of idea and  i think it could make a good hit because porn sites now are starting to accept bitcoin as their payment method to be able for their users to enjoy other privilages like buying a vip membership or premium accounts to access those high quality restricted contents that only available for paid users. it is also better that any other payment options like credit cards or paypal as it does not requires any valid information or anything hassel and stressful things.