I think it's the relatability. Many people can imagine their homes getting damaged or their businesses facing disasters. When they see these real stories in the commercials, they can easily put themselves in those situations. And Farmers Insurance solving those problems gives them a sense of security. For example, the story of a family losing their home to a natural disaster and Farmers Insurance helping them rebuild is very relatable to most homeowners. It shows that the insurance company understands the importance of people's properties and is committed to helping them when things go wrong.
The authenticity. These are real people who have faced real problems. It makes the viewers believe that if they were in a similar situation, Farmers Insurance would come through for them too.