But PayPal has quite large fees. From a 9 USD payment, they take like 10%. Also, if you are not from the US (I am not from the US), you can only withdraw money in your local currency, and PayPal has quite bad conversion rates (you lose 2-3% again).
I am still wondering, that after so many years, no big company (Google, Facebook, Apple) came up with their competitor to PayPal (everybody would switch to them, if they had lower fees).