At this point, Dems can only hope it’s a break-even proposition with her as VP.
She lacks progressive bonafides, which will make folks in the Sanders and Warren wings of the Democratic party less than happy.
She's a positive because she is a Black woman. (Yes, she is also qualified.) Biden was not solid with the "African American community " as they say. This guarantees all those bBlack moms and their daughters will be making sure to get out to vote. As I've been saying all along there was no way he was not going to pick a Black woman.
As for Gavin Newsom in the future, certainly he'd better than the awful mayor of LA who thought he was going to become the governor, Antonio Villaraigosa or the other mayor waiting in the wings, Eric Garcetti known locally as "Mayor Yoga Pants." But in general I would say fat chance.