They are in breech of policy. They are discouraging PayPal by offering a financial incentive to pay by an alternate method. That is discouraging buyers from using eBay's accepted payment methods. Policy violation.

As all their listings are auction, immediate payment isn't an option. Therefore, I could say I want item A B and C, please send an invoice, I wish to pay via bank deposit. As soon as I get the revised invoice, I am free to pay via PayPal. Nothing they can do about it. I get a discount and the seller is left eating cheese.

I did see several sellers that I followed get shut down a few years back for doing exactly the same thing. I was quite disappointed because the sold a lot of stuff that I liked.