That's the target of this deck
Considering Gholdengo is made of gold, it makes perfect sense for it to get a secret rare card to shine and this is likely one of the most golden cards the TCG has ever made
On Rebecca's Standby Phase, the effect of "Marie the Fallen One" activates, increasing Rebecca's Life Points by 200 (Rebecca 4000 4200)
Additionally, popping a Blaine and then losing the coin flip can cost you a lot of ground 70 damage is very different to 130, after all so players who want a bit more consistency might want to stick with the old version
As for its value, the Reverse copy is unsurprisingly more expensive, but even the normal common version will cost you a few dollars
Anyone who is into collecting knows that when manufacturers make errors, those items can become very valuable for the holder