It's a great choice. She's be a solid VP. Understands the senate, can mobilize the left, both the commies and the normies. She's smart, she's capable and when I met her for 2 minutes in the SLC airport, she was super cool. I think I'm a good judge of character and she was the real deal. Genuine. I'd canvas for her. Biden doesn't do anything for me, but I'd enthusiastically support Warren.
I think it's wise. Although Warren is no spring chicken herself, Joe must be aware of his own mortality, and therefore be really thinking about presidential readiness for his running mate. I would prefer to see her as successor to Mnuchin, but I'm not hopeful that we'll see a non-Wall Streeter in that position in the coming years, even though it's exactly what we need. History should tell us that the VP usually doesn't matter, but then intermittently it matters a lot. LB Johnson, Truman, A Johnson, T Roosevelt, Coolidge, are some examples of VPs who took the presidency in a very different direction from the one people voted for when they were elevated to the presidency, some for the better and some for the worse but unarguably different. I think Joe is pretty aware of that, and (a) doesn't want a VP who's trying to upstage him, and (b) wants a policy agenda that will have some continuity in case of his demise. Trump harbors no such feelings about his eventual death (or about anything?), and therefore picked the guy who some consultants told him would help get him votes and only ever show complete and total fealty.
I think Warren concluded beyond a reasonable doubt that it's better to piss out than piss in when her confirmation hearing went full partisan bullshit. If nothing else this would put her in the running as Senate tie-breaker and she undoubtedly has a better understanding than most of what a useless legislator and leader Biden truly is. Warren interests me because she's pragmatic to a fault. She thought she'd change the world as a laywer. She did, but not enough. So she became an educator, which also wasn't enough. So she tried to become a bureaucrat - it wasn't enough. So she became a politician. And this is a purely political ploy.