I have read references to this feature on some Canon DSLR cameras and am wondering what benefits or uses it has.
Canon has introduced a new feature coined EOS iTR AF - Intelligent Tracking and Recognition Auto Focus on the Canon EOS-1D X DSLR.
EOS iTR AF is also now available (as of April, 2019) with the EOS 1D X Mark II, EOS 7D Mark II, EOS 5Ds/5Ds R, and EOS 5D Mark IV.
The camera attempts to detect the locations of faces and focus on these in the scene or alternatively it can identify subjects of a particular color such as in sporting events for example. Face detection is given the highest priority, but if this lock fails it will fall back to looking for the color information.
The default AF mode for the EOS-1D X uses phase detection AF information, but the secondary option uses the face and color detection of the iTR AF. This feature is achieved by using information from the RGB metering sensor as part of the AF system.