Obama used him as insurance because he knew he was so bad.
Honestly I would rather have Obama than the Biden.
and I never thought I would have to say that.
But he did nail it when he said “Don’t underestimate Joe’s ability to fuck things up.”
https://www.politico.com/news/magazine/2020/08/14/obama-biden-relationship-393570
I think Biden is doing the same with Kamala. That's the only reason why I think he chose her.