Essentially it's a slightly more expensive copy of whatever instants and sorceries you've cast so far, and spellslinger decks are going to have so many options it isn't even funny
You're not playing anthem effects like Intangible Virtue just to sacrifice the recipients of those bonuses
And I can see the 30th Celebration Charizard potentially being worth even more on the secondary card market at first, driven by the sets likely insane demand (think Ascended Heroes level hype but much worse) and the clear bankability by Pokmons original chase card
Given this, so long as the solvent used to remove a portion of the signature doesnt change the card itself, I probably wouldnt lump it together with other things that physically alter a card (e.g
Tifa's last ability doesn't give you any additional main phases
This guide will help you with the best of them, blue, but the world is your oyster