Maybe he had to deal with C/C++ APIs. He does flat out say the two main modern languages are Swift and Objective-C. I know using OpenCV from iOS is a real nightmare for this reason.
C libraries are fine in Swift, but I feel that dealing with a C++ library (and non-CF/system C libraries) is usually a rare exception when "writing an iOS SDK". Most iOS libraries are just written on top of Foundation and the appropriate platform interface kit (if it's a UI library).
