I don't mind short movies. I also don't mind shows that have fewer episodes. Sometimes you can have all killer and no filler. Now, long movies or shows with tons of hour-long episodes can be fine as well, but I appreciate stuff that doesn't require a huge time commitment. "Venom: Let There Be Carnage," was a breezey 97 minutes with credits, and that was just long enough! Hence, when I hear, "The Batman," is two hours and 47 minutes--without counting the credits--that just sounds like a big commitment of time. I mean, the Zack Snyder cut of, "Justice League," being a smidgen over four hours has scared me away from it, to be honest.
I don't mind long stuff, I just appreciate it when something is less stuffed. The same thing stands with video-games. I don't need a 100-hour epic journey, just give me something tight, focused, and fun. For all I know, "The Batman," needs every minute of its runtime to give us the best experience possible, so don't think I'm complaining (just a tiny bit, maybe). Whether it's long or short, "The Batman," looks promising so I'll want to check it out at some point, regardless of runtime.