@lolmaolol : it's been a while we didn't see Nie Li fighting alone. The last battle was more the whole city fighting and him giving the final blow through the array.
Even if the encounter doesn't advance the story further it'd serve as a power check (for us and MC). And maybe with some luck it'll add some story elements.
But yeah, if you already red the LN, you already know if it add things or not in the story and you don't need the power check (since you know it already).
This part maybe not for you, but for me, I like it