Can anybody help me as to why I am now considered a guest of Paypal when paying by credit card

[14klippi]

I have been a Paypal user since joining Ebay years ago and over Xmas having purchased a few items and paid by Credit card through Paypal,  have been advised that I am considered a Guest and have been advised to join Paypal???.  I contacted them and was told that I am considered a guest because I used a Credit card for payment (I do have money in my Paypal account but I prefer to use my credit card.)  I cannot understand this and when I queried it the second time, they couldn't give me an explanation.  As a guest of Paypal I am not covered by the new Ebay money back guarantee as advised by Ebay when one of the items took some time to be delivered.

Can someone help with an explanation please.   Thanks