I saw part of this press conference and while his staff billed it as important, I don't believe Biden did himself a lot of good. I mostly concur with several of the columnists at PJ Media who live-blogged the presser.
They concluded he did just well enough to enable him to keep running, without changing many minds about his underlying neurological deterioration. It was okay for him, his version of a "good night," but for anyone else for whom the bar is set higher, it would have been a flop.
Democrats are beginning to figure out they're stuck with Biden and he will very likely lose to Trump. Nate Silver currently gives Trump a 0.71 chance of winning, where 1.0 is certitude.
The Democrats' rending of garments, gnashing of teeth, and wailing will be music to Republican ears.