Are there benefits for buying organic cotton items rather than commercial cotton?

Absolutely!
The commercial farming of cotton accounts for over 10% of pesticides and 22% of insecticides sprayed annually, though it is grown on just over 2% of the world’s arable land. In the United States, where cotton heavily is farmed, it’s commercial production accounts for over 25% of pesticides used annually.
 
Every year, heavily sprayed cotton plants are woven into garments and bedding for consumers to purchase. Roughly one-third a pound of pesticides and fertilizer is needed to produce enough cotton for a single t-shirt. Meanwhile cottonseeds are pressed into oil for packaged foods and salad dressings. Dairy cattle and livestock are fed a large portion of inorganically milled cottonseeds, introducing toxic pesticides that are banned for use in food crops into our diets. The toxic residue from cotton production pollutes soils and kills wildlife,but perhaps more disturbing is that the World Health Organization estimates that 20,000 cotton workers die every year from contamination.

Given these facts, it is easy to see how wearing organic cotton is more then just a fashion statement.