The use of synthetic fertilizers and chemicals in your landscape will ultimately make the soil more dependent on those products. Also with chemicals there is a potential for unused or over applications to leach into our groundwater. Soil that is comprised of just 4% of organic matter (or humus) can hold up to six times its weight in water as well as improving its nutrient holding ability.
Organic management of your turf will in time restore the biological and microbial balance that nature intended. Healthy soil and turf will out-compete weeds and produce enzymes that breakdown thatch. However, the most important benefit of having an organic lawn is to help protect your family against contact and absorption of chemicals through their skin.