I don't need a diesel either, but I wanted one and was willing to pay for it. I am not sure about the cheaper oil thing since the the 6.4L requires more expensive oil and it only cost me $70 to change my oil at the dealer every 15k miles.
For those living in colder weather and have a Cummins I would recommend remote start, butt warmers and a custom tuner. My custom tuner changed it to automatically kick on the exhaust brake when remote starting it below certain temps which warms up the truck quicker. Not only that, but he programmed my butt warmers and heated steering wheel to come on when I remote start it below a higher temp than the stock temp setting. They are usually nice and toasty by the time I get in and go.