Your CC is more than likely secure with the site and paypal. The paypal never asks for your pin,user i.d., or another sensitive material via an email. If you ever have a question you can call paypal directly. I've found that their customer service is fairly good.
Whenever I buy anything over the internet I use a CC not a debit card. The reason why is, if there's ever an issue with someone hijacking the account, it's not necessarily my money but the CC company's money. If this is the case then you always have the option to dispute the transaction. If it's your debit and it gets hijacked, depending on the type of bank you have, you may or may not get compensation for the loss of funds.