Kerass is more splashable than other Tri-Brigade monsters due to this effect and can be helpful in a variety of decks
Nest Ball, for example, puts the Pokemon onto the Bench directly, which means you can't use some Abilities, such as those of Dedenne-GX, Crobat V, and Eldegoss V
Legality depends on the tournament format -- Kai Budde Decklist Card can be legal in some formats and banned or restricted in others
Fairy Tail Matchlille Level 4 LIGHT Spellcaster Effect Monster ATK/ 1850 DEF/ 1000 You can only use the (1)st, (2)nd, and (3)rd effects of this card's name each once per turn
However, what makes no sense is that the same limitations do not apply to anyone else, and NPCs have huge decks filled with rare cards
I promise to make an Ooze lord the next world where the fates align