It will not be sacrificed after it has lore counters equal to its final chapter number
As far as Magic Arena goes, there isn't really a way to get the deck cheaper than eight rares and four mythics since Dorothea, Vengeful Victim, Katilda, Dawnhart Martyr, and Hallowed Haunting are the foundations of the deck, although turning a rare dual land into Evolving Wilds does help with the cost a bit there as well
You can really set up an asymmetrical battlefield sweeper here by casting something like Naya Charm or Cryptic Command on an opponents end step, then untap and cast Dont Move
That isn't why it's valuable it's a shiny Mew as a gold secret rare, and it's a total collector's piece but it is cool that Celebrations can be played with as well
The potential for Special Energy cards to be added to Pokemon TCG Pocket is also uncertain since Energy isnt treated as cards and is instead generated once per turn, separate from the players deck
IV - Mega Flare - This creautre deals damage equal to the total mana value of other permanents you control to each opponent