The latest delight of PayPal (according to a financial services advice email I get) is that, if you inadvertently use it as an intermediary in a credit card payment, for example if a retailer uses PayPal in lieu of a card service provider over the counter, or your credit card payment is 'taken' via PayPal over the 'phone, you lose the usual credit card transaction protection - no cooling off period, etc.
PayPal is not a bank nor a card payment service provider (in the UK legal sense), although I'd guess it would like you to believe that it's both of those things.