I like that so many people tend to think there is usually some unique BEST qualified candidate for these types of positions. Positions that require a multitude of talents and abilities allow for many different best qualified candidates because people tend to have different mixes of abilities and different strengths.
There may not be some unique best candidate, but if you search only one part of the candidate pool (as Biden intends to by eliminating all men and all non-black women from consideration), you are statistically less likely to find all the worthy contenders by any measure or combination of measures, unless your measure of 'best' includes having the qualities of womanhood and blackness.