Getting in and out of cars is slow, they don't fit many people, and if there's luggage or anything similar that is an extra step. Just picture your typical airport people mover as a comparison. Doors open at level, people walk in with their bags, doors shut. Previously Elon has said Teslas would drive down the tunnel for who knows what reason, but also that there would be a vehicle that looked and functioned a bit more like a people mover. I guess not.
I can't wait for this to open. Hello ADA lawsuit, also, too.