Oftentimes, upgrading a deck has some pain points where you have to cut theme cards for functionality
Only One Finds It Fun: In the "Sun and Moon" saga, when formatting the Ultra Guardians, Lusamine designs suits for the heroes that are Super Sentai-based because she thought it would be cool
The effects are solid
Granting a creature a stun counter isnt the strongest deterrent, but when players have other decisions for attack targets, this small but relevant downside comes up a lot, especially in early turns
The single-player challenges are designed purely to help players understand how the games elemental system works - which is similar to that of the Pokmon video game series - and give them a chance to use various cards found in the wider game, which is great for helping to develop your sense of play and on-the-spot thinking
Luffys popularity transcends the card game, making his cards desirable across various fanbaseswhether they are players, collectors, or manga/anime enthusiasts