you could have a huge problem with card charge backs. Lets say somebody stoles a creditcard and buys BTC. once you will get under investigation you will have to pay back the funds you got from the card plus your BTC is gone.
That's a universal issue. You can avoid this by adding some barriers like ID card verification. What do you think of the model.
or try OkPay, Payeer, PerfectMoney, Paypal, etc