Collectors often seek PSA 10 versions for their rarity, as well-centered, flawless Energy cards are harder to find
Unfortunately, this causes a lot of confusion, since the term "proxy" has been a part of Magic for a long time and the use of proxies is widely accepted for certain purposes and types of play
Knowing the difference is pretty important
Japanese cards are also often cheaper in the Western world due to a higher demand for English cards in those markets
Like most One Piece TCG cards, the value of Kuina depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Starter Deck 12: Zoro and Sanji)
If another effect sets a creature's power to a specific number or value, those become its base power