Yeah, [Mike Ash's post](https://www.mikeash.com/pyblog/friday-qa-2013-09-27-arm64-and-you.html) on the changes with 64-bit covered that well. I would argue that there is still plenty of  non-outlet properties in an app. I don't think we'd ever consider the performance difference between retain types of a non-outlet property, so why for outlets?