The buyer doesn't get any meaningful protection that they didn't get get before the BPF.
The only difference is that it was previously provided free, but now buyers have to pay for it when buying from private sellers. (Although eBay still only pays for non-delivery refunds; the seller is still responsible for refunding when an item is not as described.)
This came about when, to compete with other online sites, eBay made it free for private sellers to sell here. So they lost the fees from private sellers, and imposed what looks like a rushed and poorly thought out fee for buyers. (No, it is not returnable.)
The result is an absurdity that has enreged buyers and sellers alike. Buyers are being force to pay almost as much as some low priced items cost to "protect" them, and sellers are losing sales because their prices are being so inflated by eBay.