. . . Probably involving PayPal and BTC . . .
Imagine that I come to your website to acquire some BTC. I send you $1000 via PayPal. Then you send me my BTC.
As soon as I receive my BTC, I contact PayPal. Perhaps I tell them that my account was hacked and I didn't send those bitcoins (perhaps it isn't even my account and I actually did hack someone else's PayPal account). Perhaps I tell them that you never delivered the requested item. Either way PayPal credits back the bitcoins to the account they came from, and removes them from you and your website.
How many times could your business survive activity like this before you decide that you are loosing too much money and shut down your site?
This is why you don't find many easy ways to convert PayPal to BTC. Nobody with BTC wants to risk losing money to people who will use fraud to convince PayPal to reverse the charges (then they are out both their BTC and their PayPal money). Those who have tried generally encounter exactly the above situation and then shut down their business.