Harris is there to reassure young liberal activist Democrats that the old guy they couldn't give a shit about isn't the future.
"I'm a young, black, Asian, white woman of no particular gender that I'm going to make a deal about if you mistake me for a man. And I'm the future when we figure out a way to cleaning remove Joe without him noticing too much. One idea is sending him on a world cruise in a rowing boat to see what damage climate change is doing to our beautiful oceans, Stick with us, assholes, You'll love how this ends"