Wouldn't the nature of batman's line of work make any evidence he turns to the authorities completely inadmissible in court?
Imagine Batman doing a major takedown of a high profile white collar corrupt mob boss or whatever, he gets hard evidence and shit, everything he needs to put the guy behind jail, then what happens? The mob boss' lawyer would be like, "batman is an unlawful vigilante and criminal himself, as far as we know this man could have fabricated the evidence, how can we trust a criminal or even a man who doesn't reveal his own face?", then what happens? The case gets dismissed and all the evidence becomes inadmissible, or Batman unmasks and details every single action he took and how, landing him in jail as well as damaging greatly wayne enterprises and probably getting his shit confiscated. All to get one guy.
As a vigilante, Batman's only way to deal with things is the punchy way.