PayPal now requires all accounts to be "verified" if you every want your spending limit to be greater than zero. In other words, be useable.
But you have to give PayPal permission to take money from your back account without telling you and then they promise to give it back. They say this will be a small amount, and if it works fine. But to your bank, your account is now a "Joint Account" with you and PayPal as equal parties. Either party can "empty" the account.
You may trust PayPal, but if (or rather when) PayPal gets hacked, all your bank account money may be taken without the bank knowing anything is wrong, because you agreed to this beforehand.
DO NOT get into such an agreement! Tell PayPal they can access your credit card only, but keep their hands off your bank accounts!
Monetary Loss: $1.