That's the rates _from_ Germany to any EU country. So I wouldn't pay for a wire to France, but I don't know what a French person would pay to wire to me. The regulations only say that EU wires need to have the same price as national wires.
This is how you pay: the bank earn the interest rate for those two days.
Besides, transfers within my country (Denmark) to other banks arrives next day. If you pay for the transfer, you can get the money transferred immediately. So next day = free, same day = pay.
For free transfers I don't get interest rate for the day when the money leave my account. The recipient don't get interest rate for the day he receives the money. So even if the transfer only takes a few hours (If I pay just after midnight, he'll have the money at 6am), the bank earns interest rate for 2 days.
Banks transfer huge amount of money so the interest rate adds up for them.