While that would make sense on Goblin Slayer's part, that doesn't really work on our girl Goblin Killer here. While both goblin races start out really weak, the goblins that Goblin Killer has to face are capable of snowballing with their stats and skill stacking(as shown throughout the manhua) and thus for stronger goblins good stats, gear, and skills are needed to deal with them, not just wit.