Why aren't bank transfers instant?

Question

PayPal

Why aren't bank transfers instant? For example, withdrawing money from PayPal to a bank account takes 5 to 7 days... what happens all these days? Are they manually checked or what?

Answer 1

https://habrahabr.ru/company/itinvest/blog/253675/

Answer 2

Are they manually checked or what?

You guessed. Security checks them manually, and sometimes they call and ask for confirmation.
But if the transfer within one bank is for a small amount, then it is instant.