I'm not sure whether eBay applies PayPal by default as an accepted payment method whether the vendor likes it or not - it's certainly never seemed to gain the popularity on eBay.de that it has in, say, the UK. Typically, if I win something from a German or Swiss seller, I still more often than not end up paying by bank transfer - bit of a pain from the UK as it means a visit to the bank, but it's what they are accustomed to. If it's any comfort, I've never had any problems using it either.
Maybe one of our German-based members can confirm - does eBay add PayPal as an accepted method of payment even if you only select payment by Überweisung? It certainly looks that way judging by some of the item descriptions.