Buying undiluted coolant is much cheaper than buying diluted coolant. When you buy a 50/50 mix, you pay for 50% coolant and 50% water. When you buy undiluted, you pay for 100% coolant. Also, I live in Florida and run a 70/30 coolant mixture in all of my vehicles. Running 100% coolant has no more of an advantage than running 100% water. It's the combination of the two. Running 50/50 provides protection from -34F to +265F, 60/40 provides -62F to +270F, 70/30 provides -84F to +276.