Urriak Uruk
Gaming is fun, and fun is for everyone
I disagree. He would just need to target his action as Batman. Beating up Marcone and his lieutenants and disrupting their negotiations with and international drug cartel would be useful. Taking out a warehouse full of goons who are trying to bring drugs into the city, and disposing of the drugs, would be useful. There's a lot of punching he could be doing that is useful.
I'm personally fine with the fact that comics ignore concussive brain damage and the fact you can absolutely accidentally kill someone with a blow to the head, it's basically fantasy. Believability in human behavior is vastly more important than physical realism.
Real-life law enforcement agencies (the police, FBI, CIA) do a lot of targeting as well, and it hasn't put much of a dent into international drug cartels. I'm extremely doubtful one man (even one with near-unlimited resources) can make much of a meaningful difference in the long-term. As long as there is demand for elicit goods, there's going to be crime that capitalizes on it.
I do find it ironic you mention the fantasy of Batman, as there is no way that Batman can possible exist in the real-world. So bringing in real-world arguments about fighting crime and applying them to a character who can't possibly exist seems fairly counter-productive.
The easiest example I can think of for why Batman can't exist, is it would be so incredibly easy to deduce his identity. There's only so many people that can afford his level of tech, be the right build and age, and not to mention the guy actually shows the bottom half of his face. It would be obvious that it is Bruce Wayne. I find it so funny that Kravitz looks at Batman in this trailer and says "Who are you under there?" when anyone could clearly guess "Oh yeah, this is definitely the most famous rich guy in this city."