We drive to WDW so we always have our car. We still use WDW transporation for nearly everything, because not having to drive everywhere is a welcomed relief. The only times we DO use the car is if we have an ADR at another resort. It's wonderful to just drive straight there and back. But we use WDW transporation to all parks. My DH did take the car almost daily to a local store or gas station for something like drinks or snacks. So it is nice to have the flexibility of having a car at our conveneince, but I could totally see us being just fine flying, using ME, and only using WDW Transporation if driving wasn't an option for us. Personally, I don't see using the car at MK, because, like you said, busses drop you off right there, but I could see where it could be handy at the other parks, especially if it's park closing and you have a sleeping kid