Let's get into the central gag of 'Cautious Hero'. Seiya Ryuuguuin's caution isn't a minor character flaw; it's the entire engine of the plot and the main source of humor. His overwhelming power means he should steamroll every challenge, but his pathological over-preparation creates obstacles where there shouldn't be any. The balance isn't in him struggling to win—he never truly struggles in a fight—but in the narrative tension between his goddess companion Ristarte's frustration and the audience's dawning realization that his paranoia is, against all logic, usually justified.
It works because the caution is the power. Him vaporizing a slime with a fully-charged ultimate move isn't just a joke about overkill; it's a setup. Later, when a seemingly trivial enemy reveals a world-ending secret ability, Seiya's prior 'wasteful' actions are retroactively validated. The comedy stems from the extreme disproportion, while the story's stakes are maintained by the reveal that the world is secretly more dangerous than it appears. His power solves the immediate physical threat, but his caution is what actually navigates the hidden narrative traps.