So assuming it wasn't just completely a bluff, MC mentions both a poison and paralysis "potion"... Even putting aside how silly it is that these bottles appear to be indestructible when he launches them at a monster's head for raw damage, he never once considered tossing these potions at enemies to inflict status effects on them?
This guy is as much of an idiot as his old party, they really were a perfect match for each other.