soooo much usopp hate this chapter, but this chapter deepened the character development options for usopp. Usopp himself sees his journey as working toward going from weak to strong, scared to brave, so in turn, the audience sees his character development following that model. It seems tho that there’s more to it than that, a deeper moral than just overcoming "general fear" as the main personality issue that drives the character through the entire series. Usopp's greatest flaw is not his fear, it's his lies, I can't remember a stronger moment where Usopp saw the pure pain that his lie could cause.
There was nothing wrong with being cautious and staying hidden, there was nothing wrong with running when you know your beat, remember usopp was just on DR to delver CC NOT join an army to take down a shichibukai king he had no obligation to the dwarves in anyway… except his lie.
This shouldn’t be compared to the Chuu fight, Usopp deciding to fight then was akin to wearing the Sogeking mask, after he pretended to be down to save himself he was afraid of facing his crew if he really didn't even try to fight so he put on this "mask" of bravery. With the actual sogeking mask, he was again afraid to face his crew, he uses the sogeking mask the same way, as a "mask" of bravery, TB same deal, mask of bravery, but that time he used it to face his own fear for the perona fight.
This time tho, there is no mask, there is no costume, there is no false name, there are no more ego boosting lies, it's just usopp pure, facing his own lies, in a sense, his core.