Not sure if this has been mentioned already, but one potential positive of this new authentication service is that it at least requires that an actual physical card is being sold in the first place. Some of the fraudulent ebay listings that have been posted on Net54 recently have been for cards that were not even in the possession of the scammer. For example:
https://www.net54baseball.com/showthread.php?t=313780
One has to think that at the very least, even if ebay is not great at detecting a fake, that these types of listings go away completely.