It's durable, comfortable, easy to wash, cheap, and won't poison you with plastics. It's negative characteristics are a non issue because your base layer is too thin to absorb any significant amount of water, it's close to your body heat, and it's the innermost layer and the least likely to get wet. I wear relatively thick 100% cotton Carhartt work shirts and even those dry very quickly and don't cause me any problems in cold weather.
Cotton is a bad choice for outerwear and insulation layers of course, but it's just fine as a baselayer and there's no advantage to anything fancier. The "cotton kills" phenomenon is just retards who go out in freezing downpours with cotton hoodies and jeans.