First, most overpowered cards are still overpowered when they're restricted, so, in formats where there are only a few restricted cards, all that restricting overpowered cards serves is to add randomness to the game
Iono #350 is the clearest example of how prices shift over time
The Pokemon TCG takes a very different approach to Pokemon types than the mainline series, with types like Metal, Lightning, and Darkness only present on the TCG side
Note, however, that its utility is the same as the far less expensive version that comes in the Starter Kit
The Pokmon Mega Evolution Phantasmal Flames Elite Trainer Box Includes The Pokmon Mega Evolution Phantasmal Flames Pokmon Center Elite Trainer Box includes: Other formats include Pokmon Mega Evolution Phantasmal Flames expands the Mega Evolution era with more cards and gameplay mechanics
That said, past precedent has shown us that Welcome Deck cards can be worth a lot regardless of their playability