The translation seems like there's some gaps here and there. Page 24 for example. You want Don't You?
You want what? Power? UOOOOOOH TAKESHIIII SEEEEEEEEGGGS? Happiness?
I mean it just seems abruptly cut somewhere.
And also, clearly his power is already established to be crowd control and battlefield setup even before we get to his Arrow Trap. There's not enough to justify exactly why his power is considered of little value. If it was just the activation that's the issue, that's not a major issue. That's still a threat on the battlefield that the enemies are clearly aware of as seen by this low ranking monster. If it was still a threat that caused the battlefield to be controlled and the enemies to be funneled, the value of it is still incredible.
If the party breaks down just by his removal and they get surrounded, then we have confirmation that his trap were still threatening enough that despite a near 200 level gap, it was still meaningful. In that case then it was a matter of doing some grinding and funneling enemies into his traps.
We need more clarity. Is it the number of traps he can deploy? Is it that it actually doesn't do enough damage to begin with? As someone who enjoyed Tecmo's Deception series (and the one off Trapt on PS2), I can't help but think this is intellect and skill issue on both the MC and the party's part.
But hey, slop is slop. So when does he meet up with the random girl he bumped into who'll clearly be the main heroine again? Will his party consist of the typical 3 heroine harem, of which one of them is the leader who dumped him and returns back and decides to be subordinated to him?
And if anyone wants a good way of explaining things, worldbuilding, setup and actually mature reasonable characters, I would recommend "Welcome to the Impregnable Demon King Castle". It's a good read.