I NEVER use a debit card anywhere. It is so easy for criminal types to 'catch' the debit card info from the 'air' when you use a debit card and your checking account can be cleaned out very quickly if they do.
At least with a CC there is a limit to what you are responsible for paying if your card is hacked. But banks aren't very willing to replace your balance in your checking account when your debit card is hacked.
I've never used paypal. My DH has an account, so I can ask him how it works.