The reason why Paypal initially succeeded is because it’s a nuisance to have to input your credit card number every time you make an online purchase. Also, it accomplished this end without seemingly compromising your sensitive financial information. However, with this convenience arrived a host of problems, especially for the vendors accepting payment. The biggest reason is because PayPal is NOT a bank and therefore not held to the same standards as one. It has much more latitude to fuck up and fuck you over.
Which it seems to do with great regularity.
Reading countless narratives from angry ex/users is an exercise in monotony (unless you’re an insomniac), so I pulled these very brief and illuminating explanations from ex-PP employees. If they don’t make you reconsider manually typing your Credit Card number, I don’t know what will.