Batman does not have to be in the dark. In TDKR, he fought Bane in broad daylight. So being in darkness is actually his choice, and of course there are also factors of necessity. The first is the reason why he actively chose to be in the darkness, which is closely related to the training he received from Ra's al Ghul. (The movie I have has external subtitles and no dialogue...just a text description) Bruce Wayne learned two things from Ra's al Ghul. The first is "In order to fight crime, you need to become a bigger symbol than 'a person'"; the second is "In order to defeat fear, you need to become fear itself." Throughout the trilogy, Batman also learns a third thing, "Strength comes from one's fear." The unity of these three ideas is Batman: a symbol of fear. In other words, the reason why Batman is the image of a bat is because it makes people afraid. And the night and fear are the best partners. The dark night can hide a lot of information about oneself, making oneself "more than just a person", and can also bring more fear to people. In addition, bats are originally nocturnal animals, so the image of Batman was determined and he chose to do it at night. Fighting is a matter of course. The second is the compelling reason. On the one hand, Batman's mask can protect his loved ones from harm. On the other hand, he was defined as a vigilante in the first part. In the second part, he was not favored because of the Joker's framing, hostage rescue, and Harvey Dent. , in the last part, he immediately became a murderer and was hated. So even if he wants to take to the streets in broad daylight, he can only do so after the final war in the third part begins. The above is an explanation of "why Batman must be in the dark" based on the plot of Nolan's Batman trilogy, but to answer "why he is not like Iron Man", or "why Batman is this image", We have to answer it from a perspective other than the plot. Condensed into one sentence, it is because they have different strengths. Of course, their abilities are different, but the director’s ideas are different.