That actor is not a celebrity though. In fact she is practically anonymous. She was not hired to raise the visibility of the product or lend it credibility via her celebrity. A large majority of people in the US would be quite familiar with Tom Brady, Giselle Bundchen, Shaquille O'Neal etc. Almost nobody could name who the actor is that plays the woman in the Progressive ads without Googling it.

Any celebrity or person whos is willing to endorse products and services for large money money should have a counsel whose business is to know how to do these things.