I find it hard to believe you _only_ use Septa to get around Philadelphia. I have the regional rail pass for my commute as well and Philadelphia's public transportation system is not great for getting anywhere in the city. I uber all the time to get around Philadelphia to supplement my Septa pass. It still definitely beats a car payment, insurance and the hellhole of parking though.
At least compared to NYC, where I could hop on the subway to anywhere in the boroughs.