Just a guess, but she is the candidate only because of an agreement she demanded of Schumer, Pelosi, and Obama when they threatened Biden to resign or face the invocation of the 25th Amendment. The VP must be part of the group that invokes the 25th or it cannot go forward. So without Kamala, there could be no 25th Amendment threat to Biden...and he would still be the doddering old fool of a candidate for 2024.
The Democrat Party replaced one fool with another and is probably working diligently behind the scenes to develop of plan B in case Kamala bombs.
She’d get eaten alive on stage by somebody who knows her record and has the guts to articulate. If she were to win, she’d be very difficult to handle by those who put her there. I hear she’s pretty mean and abusive.