When a Wizard character uncovers another Wizard's spellbook, you can hand them a stack of spell cards to represent the actual pages
at some point, somebody who has one of the promos will want to sell them, so you can find listings on sites like eBay and TCGplayer
[58] "The Pokmon Demo Game Plastic Pack", "Base Set", along with the subsequent expansions "Jungle", "Fossil", "Base Set 2", "Team Rocket", "Gym Heroes", "Gym Challenge", make up the "First Generation Sets" published by the original English-edition publisher Wizards of the Coast
Springheart Nantuko is a very strong card
And if this -15 printing variation only applies to the thick stamp holos, then can we really class it as a smoking gun for the first print run, since it excludes 86/102 of the cards in the set from ever being considered true first editions