There were reasons not to pick J. D. Vance, but he’s inarguably a good spokesman for the ticket, and he’s shown it the last couple of days.
Pivot and attack, rinse and repeat. That’s been the basic approach. You can see it here where he deflects and redirects Walz’s attack on his Ivy League education and here where he does the same regarding Trump’s dumb attack on Kamala’s racial identity.
The race isn’t going to be won or lost based on Vance’s performance, but at least one half of the ticket is out there hitting the right notes.