Haven Sleep interview questions

The first interview went great; the marketing manager called and was friendly, explained the company and position in detail, and asked pretty standard questions. I moved on to the next stage, where I received a call directly from the founder. They seemed to be making the call while they were driving somewhere and this interview was much less structured. First question was the ol' 'so tell me why we should hire you', and ended with him asking me to submit a proposal for a project I could do as a test.