Technically, that means I'm spoiling the plot, but if you're playing a Pokemon TCG Game Boy game for the plot, you're doing something wrong
[16] Steel-type Pokmon are immune to Poison-type moves, and they have very high defense and resistance to other types, while Dark-type Pokmon are immune to Psychic-type moves and are strong against Psychic-type Pokmon (which provides an offensive strategy, formerly absent against Psychic-types), as well as having few weaknesses
Lots of new collectors jumped into the hobby with cash in hand but no real concept of the difference between eBay asking prices and actual values, and the prices they paid upped the actual value to heretofore unheard of levels
Thats why even a Poor version of the card is worth 19.000
Adding salt to the wound, this was a TCG-exclusive card