This configuration produces a completely mono-compatible signal and, if the Mid and Side signals are recorded (rather than the matrixed Left and Right), the stereo width (and with that, the perceived distance of the sound source) can be manipulated after the recording has taken place.
This setup enables the creation of a mono-compatible signal. Additionally, by capturing Mid and Side signals instead of Left and Right signals, which are combined in a matrixed format, it becomes possible to adjust the stereo width and thus the perceived distance of sound sources after the recording process has taken place.