Anybody with a good sense of humor is one-up on their competition. We respond to somebody who has the ability to make us laugh. It's a bonding influence.
It's mandatory in this day and age to be considered to have a sense of humor and to demonstrate it. You're not paying me for a joke, You're paying me for the right joke.
Nowadays, you cannot be a very Effective political figure without Having a demonstrable sense of humor. People take to it.