Since its vastly easier to obtain English cards in comparison to Japanese ones when outside Japan, the target market for English cards is thus larger because it includes a wider swathe of competitive Pokmon TCG players
The key to make this work will be cards like Kelpie Guide to untap Yue and use it multiple times in a turn
Furthermore, when it is sent to the GY, players can target a Fire-attribute monster in the GY and place it in their spell/trap card zone face up
Triggering for both players means it DESTROYS the mirror, and is worth mulliganing for in that match
Worst case, you got to use them for several years and theyre still worth $70 each
As the game has evolved, the rarity system has expanded from the original tiers to 8 official tiers , plus special classifications for promotional and scenario-based cards