Many sounds are more compelling when captured in stereo.
I use three different kinds of stereo mic techniques, all of which are applicable to field or studio work. XY XY stereo micing is one of the most common techniques used. The resulting pattern gives a wide, directional coverage in front of the mics while attenuating sounds coming from the rear. In field recording, XY micing is a good choice when a directional pattern is required. However, the variation in a cardioid capsule's off-axis frequency response tends to color ambiences somewhat.