Given $9,000 to upgrade to 75 battery, I can better use that $9,000 toward the $10,000 upgrade to make the car self-driving, and I can do more work while the car drives, freeing up some of my time, and the self-driving protocols will use less energy than my active driver driving styles. This will be a better value than upgrading to 75 battery for the same price, and the range will be even better, considering a self driving Tesla can drop me off and go charge itself somewhere while I'm at work or an errand, and come back to me with more battery charge level than if I was driving and parking myself. (Making me drive the same way a self driving Tesla will drive would put me to sleep, and I would not be a safer driver that way.)