They sort of have to do this because they were getting nowhere. Not to say they don't want to regardless, but they hit the limits of what their existing investigation could do.
We're all quite familiar with Hunter Biden's nonsense. There are a couple specific things around that connected to Joe Biden:
1) There is a whistleblower report from a confidential informant stating that a foreign national claimed to have bribed "the Bidens" $5,000,000 each. Chuck Grassley claims the document states there are audio recordings of the Biden's, mostly Hunter but 2 of Joe, in the possession of this foreign national. The FBI will not release this document, will not give it to Congress, and agreed only to show the document to a select committee under supervised conditions.
From Chuck Grassley
How CNN chooses to report it (I wish I could provide something better here, but most main stream media have seemingly ignored the story entirely.)
2) There is a single email from Hunter's email which connects Hunter to Joe's work in Ukraine as Vice President. The email contained Joe's schedule for a day as Vice President, which included a phone call with the president of Ukraine. It was sent by a White House aide to both Joe and Hunter Biden, and there is a perfectly reasonable explanation as to why outside of corruption they may have done so. But the thing is, it wasn't sent to Joe Biden at his normal email, it was sent to a Joe Biden alias email address. So after discovering this email alias, the question was "why is Joe Biden having official White House business go to an alias?", and they said "that's totally normal, it's still all documented, the National Archives have all those emails". To which the Republicans said "ok, can we see them?" And were told no, they aren't allowed to see them. Not even the non-classified ones.
Time's piece on this (Again, most main stream sources refuse to even acknowledge this going on, but this Time article is pretty good, kudos for that.)
So that is where we are on multiple fronts. None of this is evidence of wrongdoing by Joe Biden, that much is true. It's even possible that multiple Bidens were bribed millions of dollars while recording conversations with Joe Biden without it being evidence against Joe, as Hunter was known to work overseas with his uncle involved, and we know from Devon Archer that Hunter would call Joe Biden on speakerphone during "business" meetings as a power move. The use of email aliases may be perfectly normal, I have no personal insight into that, and the schedule referencing the cabin where he met Hunter later is a plausible explanation for sending it to him.
A third facet that doesn't directly tie Joe Biden in is the way Hunter has been investigated.
IRS whistleblowers claim their investigation into Hunter was impacted by the Justice Department, and
a special counsel has been appointed for the rest of the investigation into Hunter Biden, but notably it's the same U.S. Attorney that was already running the investigation, which goes against the precedent of bringing in someone from outside of the government as special counsel.
So this is how the impeachment inquiry gets justified: the IRS, DOJ, FBI, National Archives, and the US Attorney in Delaware all have something going with the Bidens, and could potentially have information that incriminates Joe Biden. All of those agencies are trying to keep the information they have internal, and and will not disclose things to Congress. All of those agencies are part of the Executive Branch of government, meaning that at the top, Joe Biden is effectively in charge of them, which is an issue if you are investigating Joe Biden. The constitutional check Congress has against a sitting President is impeachment, so the way for Congress to legally penetrate these agencies is an impeachment inquiry.
Do I expect them to find anything to incriminate Joe Biden? No. Is the inquiry justified? Based on the behavior of those departments, there is a strong argument for it being necessary.
www.theguardian.com
