A tip I have for this game - Play on Hard mode!!!
I ran throuhg it on Normal, and I collected about 95% of the chests in the game, all which hold health potions and stat enhancers for battles. I never used a single one of these. Due to the ATB system like Grandia (I love this system btw) it can make the game incredibly easy.
I think, if played on Hard mode you might have more of a reason to hunt out chests as you may need the items they hold. On Normal, you might as well just ignore all chests as they won't offer you anything worthwhile.
I still really enjoyed the game, but feel I missed an opportunity slightly. Would certainly be more fun if it was harder