I think I read on another forum that they’ve already been doing a soft launch of this for watches - a guy had bought a watch through the service and suspected the watch wasn’t right. Sadly the example tested ended up being an awful fake which would have been confirmed instantly if the third party had bothered to open the back.
Not sure I would be happy either paying for the service, accepting the longer lead time for delivery, having some third party of questionable skill open a watch i had either bought or sold.
Plus it’s an eBay service so you can guarantee poor comms and some element of unfairness built into the process.