I think they are trying to kill Biden with 1000 cuts.
Since he won't voluntarily step down just yet, some Dems are still pretending to support him.
In this "big boy" interview, which has quite a negative connotation, he will not have a teleprompter or note cards.
Maybe they won't actually give him the questions in advance this time?
He will be replaced, but there is no rush...
They need to get consensus on the plan, and whoever replaces him will get a little "honeymoon" period where the press goes crazy over the new and improved candidate. The convention begins 8/19, and early voting begins 9/20, so the timing is great if it takes a bit.