Mr. Biden no doubt chose her to try to appease and inspire non-white Democrats, who are now about half the party. The Democrats lost in 2016, when the ticket was all white, in part because black voter turnout went down from its 2008 and 2012 levels. The party will not want to make the same mistake again.
Sen. Harris’ main “qualifications” appear to be her sex and race. She has very little experience, having been elected to the Senate only in 2016. She is not from a “swing state.” Her bid for the presidential nomination went nowhere; she dropped out before a single vote was cast. She also memorably attacked Joe Biden as a quasi-racist during her brief run ...
https://www.amren.com/blog/2020/08/joe-biden-kamala-harris-race-regionalism-american-politics/