Paypal and credit cards

Why is it that Paypal will not allow you to use a credit card that has been previously entered into a Paypal account?

Long story somewhat short, my friend hit his spending limit and tried entering a new card. They started him on some sort of verification thing where they charge $1.95 to your card and on the transaction description is a special 4-digit number. You then enter the 4-digit number into a Paypal form, I suppose to prove that you are the person handling the billing for that card. Then they credit you the $1.95.

Trouble is, he got antsy and deleted the card before I was able to explain to him what the $1.95 was for. And Paypal will now not accept either card. He’s spoken to Paypal on the phone and they tell him that he can’t use either card because they’ve been previously used before.

How is this logical? If he owns the card, what does it matter? Any other business will allow you to switch cards for each transaction if that’s what you want.
What Paypal really wants is you to get their charge card, but the terms are pretty bad. They also want you to give them your bank account number, he didn’t want them in his real account so he just set up a new account with like $5 in it. That generally worked, but occasionally Paypal would try to charge the bank account instead of his credit card, which would result in a $40 overdraft fee that he had to talk the bank out of. Didn’t happen every time, but after 3 times he closed the account.