couldn't'a worn tights in the movies, i think---you'd need a guy with the right build. o boy would that guy have to have a build. they wanted a big name for the role (unlike when they did the superman movies, taking an unknown actor for the role), so who are they left with? Ahnold? 😱 so! it's body armor. i think that's why they chose armor for the movies. couldn't find an actor with the right build. (not that i think they spent any time looking for one like that!)
er....when i write batman fanfic, it's body armor, and that cape is a tool. a bit of help in guiding free falls, adjusting his angle, but in my stories it's more a case of taking it off (yes in my stories it comes off separate from the mask/hood) and there are pockets along the top that hold packs of a chemical that he squeezes and bursts the packets and floods the chemical into "veins" in the cloak and it warms up enough to prevent hypothermia/shock in, say, a 90% naked rape victim. or some such.