How many actual iOS devices do you use these days for testing your apps before submitting them to the App store? Xcode builds 2 different executables (arm7 and arm64). For several months out of each year, the most current iOS version is not the most dominant OS version. And there are 6 different sizes of display (3.5,4,4.7,5.5,7.9 and 9.7). That's a lot of combinations. Do you depend on beta test people (where you can't directly debug)? Then again, a lot of developers depend on the iOS Simulator (which runs x86-64 code) for some, many or all device variations.