It was the obvious choice, and the correct one. I predicted it months ago. So did lots of other people.
The best thing about Biden as a campaigner is that he doesn’t overthink things. For example, he’s staying in his basement and letting Trump hang himself on TV every day. It works, so why stop?
The tricky thing about the VP choice is to avoid saying anything negative about any of the other contenders. My guess is that he will refuse to answer questions on that topic. Whether his staff can be relied upon to do the same remains to be seen.