The email screenshot above mentions sellers fees, so I was asking if it’s for shoppers on eBay too.
What’s so complicated?
ETA: I just googled it and saw that it’s across the board.
I saw what you asked. It simply wouldn't make any sense to say, it's only including the seller.
Additionally, It said: "we'll no longer accept American Express as a form of payment". Which is certainly indicative, that it's across the board.
Anyway, I do agree with you, that they should have written it in a clearer fashion.
But I would say, the reason they only mentioned the seller, regarding updating their payment info, is because the sale would be delayed, if they only start changing their CC info after the sale was already made. Whereas the buyer, he wouldn't be delaying the sale, as he won't be able to make the sale, until he has a accepted payment method set up.