I just upgraded from a 2006 C-Class to the 2017 CLA250. I was given the option at the dealership to purchase the Garmin SD card. I felt like ~500$ was a bit much for an SD card with maps so passed. I have Apple CarPlay and can use my Maps app. What can the expensive Garmin SD card do that I cannot do from my iPhone via CarPlay? I've seen some of the brand new SD cards on eBay for around 100$, would it be worth purchasing one or would I be just fine using my iPhone as a GPS?