The forthcoming House proceedings will likely go nowhere. Thus this Mueller/impeachment fiasco is effectively over.
Notice how Trump has not declassified FISA warrants et al. He has delegated that job to Barr, and Barr hasn't either. The ending of the impeachment fiasco now clears the deck for Horowitz to issue his report and for Durham and Barr to complete their investigation and declassification to occur. That is the big impact of today.
Trump is extremely calculating. He never fired Mueller because he knew the truth and he also knew that firing Mueller was just what Dems wanted to happen to impeach him. He has now let Mueller peter out (literally, it appears), and Barr now has freedom to move and cannot be criticized for acting before Mueller was done. For example, Comey was a witness to the alleged obstruction. Had Barr charged Comey with leaking CI and lying to Congress *before* Mueller was done, all hell would've broken loose. But he let Mueller finish.
It's now Horowitz's, Durham's, and Barr's move. Notice I did not say Trump's move. Trump is a bystander in all this going forward. He is a tweeter and nothing more. The big decisions will be made by Barr. All Trump did was appoint the right AG, and he can sit back now and watch the AG go to work.