They are really hard to pull, but even then, some of them might not be rare in terms of price, as these are determined by various factors such as the art, the usefulness, or the Pokemons popularity
Gold Pokmon cards come in several forms: Secret Rare gold cards (often numbered above the sets print run), gold star cards from older sets like EX Dragon Frontiers, and full-art gold illustration cards from modern sets
This is easier to help accumulate poison counters than attacking for infect damage with the potential of your opponent blocking your attack with a creature they control
The question is, where does he fit
Professional graders at PSA, Beckett or CGC check every detail, from the sharpness of the corners to how well its centred
250 damage is a hefty amount, and it only gets better when you are able to attack into a Duraludon VMAX (Evolving Skies), and they cant OHKO you back