With their extensive seller network, you may have access to competitive pricing and the ability to compare prices across different sellers
The card even floats, as you can read below: Unaffected by card effects, except Mathmech cards, while in the Extra Monster Zone
Free spells like Deflecting Swat and Flawless Maneuver are impactful upgrades if you have access to them
In the end, I agree with you, the buyer has full transparency when bidding/purchasing
I think this time Pokemon really did a great job making the pre-release promo cards because all of them seem to be playable especially Koraidon for the Ancient Box, Miraidon for the Future Box, and Metang for Origin Forme Palkia VSTAR
Currently, these are the only four rarities of cards that can be shared