I want to believe this will reveal people who do tax fraud or potentially illegal tax dodging schemes
It's probably the quickest way to punish those people, just regular data leaks from the tax bureau.
I'm probably too optimistic, since this data is probably not admissible in court.
A similar hack created The Panama Papers. Not much came from those either. Like the Epstein Files, it may make for interesting reading, but I don't expect much legal action.
https://en.wikipedia.org/wiki/Panama_Papers