The formulation of cleansers vary as some contain more oil dissolving molecules and less water replying molecules. Although cleansers are formulated to remove oil, makeup and debris, using only your fingers and rinsing with water does not allow for a deep cleanse in and around the nose, mouth and eye and hair line.
Residue from the cleanser and makeup often settle in these “outer limits” resulting in blemishes because they are easily missed during rinsing, and have nothing to bind to when you are just using your hands.