While I'm glad that the House finally got their hands on them (they should have gotten them in April 2019, when, by law (see 26 U.S.C. §6103(f)(1)), they were entitled to copies upon the House Committee's written request, but Trump managed to tie up the request in Court for almost 3 years), I don't know what they will do with them. The original request was for oversight and to look into Trump's conflict of interest when he was still in office. But with Trump out of office, it is too late for that. And with the Democratic-controlled committee disbanding next month when the Republicans take over, there isn't really time for much else.
The law the House used to get the tax returns doesn't let them make the contents of the return public. Rather it specifies the returns can only be reviewed "when sitting in closed executive session" unless they get permission of the taxpayer (i.e. Trump) to make the contents of the return more public, and there is zero chance that Trump would do that. I guess if they see evidence of a clear crime, they can refer the matter to the DOJ before the clock runs out on this Congress. But given how the statute is worded, I don't think the House can hand over the returns with the criminal referral. The DOJ would have to make their own request for tax records, which Trump might be able to tie up in new litigation for a few more years.
I guess the House's effort made a nice precedent that might help in the future. But it isn't going to do much to "get Trump" right now.
