[addandsubtract]

Paypal is useful, because it transfers money instantly. Sending money in an envelope isn't an option when you want something instantly. As a buyer, it also offers a form of protection from fraudulent sellers, which you also don't have with the postal service.

[Dah00n]

I can do that with other services too without risking PayPal though. If it is national transfers I can both use a national payment app or even a bank transfer - both instant transfer.

PayPal might give some protection but it also freezes some accounts and keep the money. No other service I have heard of have as bad a reputation.