If one is selling rather than buying, PP gift payment is fine, because it gives no protection to the buyer. Selling and using the Goods & Services of PP where fees are incurred by the seller is where the buyer can do a chargeback, if they're going to scam you. And 9 out of 10, they fall on the side of the buyer in those cases.
Bank transfer is fine on BC if you have decent sales feedback / a track record. As is Paypal gift. Both require trust that the seller is genuine
You cannot insist on Bank transfer on Ebay. Its either Paypal ( with fees ) or cash only when collecting in person. This last option naturally cuts out many many potential buyers