Paypal is a terrible organization that has been setting itself up for a huge class action lawsuit for a while. The problem with Paypal is very simple. As a seller, you have absolutely no way of verifying that the buyer is the actual buyer, but you are held financially responsible if they are not. So what happens is people are constantly using stolen paypal accounts to make transactions. Paypal then reverses those transactions 24-48 hours later. Paypal refuses to give you any information up front about the buyer (the very same information that they use to verify that it was a stolen account after the fact, the very same information they use to flag the transaction and alert the real owner [but not the seller]), or any information on the criminal after the fact without a court order. So as a seller, there is no way to protect yourself against people using stolen paypal accounts. They are protected by the walled garden of paypal. Even though they have complete control over the security of their site and are the only party with the information required to verify whether an account is stolen, Paypal avoids the cost of their negligence and forces this cost on the helpless merchant. Paypal enables criminal activity and takes no financial responsibility for criminal use of their product. They don't even have the decency to share information about the person who committed a crime against you. Meanwhile, the merchant is left helpless. They have no way of getting the information necessary to verify the customer, no way of getting information on the criminal after the crime has taken place, and no other service to turn to because of the monopoly paypal has on international transactions for Americans.
No other services offer international transactions for Americans (maybe this has changed in the last couple years but I doubt it).
So if you are an American selling goods on the internet and you want to protect yourself against criminals, the only way to do it is to use Bitcoin. If you know of another way I'd love to hear it.
BTW: Bitcoin transactions are irreversible. A monopolist, like paypal, can't come in and just reverse the transaction after you've already sent the product to the customer.