Admittedly, you don't get to see the carrier which is supposedly being used with Simple Delivery, which is definitely an issue, however you are still protected by eBay's Money Back Guarantee if the item is lost or damaged in transit just the same as you would be with any other purchase on eBay.  If the item is lost or damaged in transit or doesn't get delivered for some reason then you will be refunded.  If the item shows as delivered but you haven't received it then that isn’t as straight forward to deal with but that applies whether or not the item was sent with Simple Delivery.