Well, a VP actually has no real job except being there to replace the President should he be incapacitated in any way and to be the tiebreaker for the Senate.
Hence why in the past the position was often used to kick some people upstairs they wanted to shut up and out for 4-8 years. Of course, this tactic has the drawback that if the president dies, then the troublemaker becomes the president. This tactic however has backfired so often that it's not used for this purpose anymore. For instance, Theodore Roosevelt was hated by it's party and thus chosen to be the running mate of William McKinley to lock him out, but then became President after after McKinley got assassinated.
As such, choosing a VP these days is mostly to find somebody with enough appeal to voters which don't necessarily vote for the presidential candidate. In Biden's case, a progressive black women would be the choice to garner more votes of people of color, of women and of progressives. Trump did the same, he choose Pence to garner the votes of the religious right (and religious people in general) instead.
Yeah, I get that it is pretty much all about the optics these days... I just kinda feel like that with Biden’s age it should be taken a bit more seriously. He should have started from a wide pool of candidates and vetted it down from there. If it still ended up being black women, great. I would have at least known he took a look at others. I just don’t like the fact that he limited his pool of candidates from the start...and those limits were fairly superficial...
While it would be exciting have a black female as a VP candidate, I know from experience that those basic characteristics fade quickly. I remember thinking it was pretty cool when McCain chose Palin, a female to be his vp. That feeling quickly faded when we started learning about her. Palin would have been a trainwreck. Glad she never got close to the presidency.