Isn't Baten Kaitos like a trading card game, how does that work?
Not really, no. It's a jrpg, and your moveset is taken from cards in a deck. That's the only part of it that really has a tcg feel. You can buy the magnus (what they call the cards) from any shop like you would equipment in a normal jrpg. Otherwise, you level your characters, gain special skills (from cards) as you get further in the game, and all that jazz. It's just very, very well done. The battle system is actually fairly tricky, the semi-real time setup takes a little getting used to, but its' good.