Humidity in So. Indiana is much like Florida, specifically the Gulf Coast, in the summer. But if it's hot, the A/C runs and by and large, takes care of it.
It's the in-between times that are a problem: cloudy, cool, rainy, springtime when the ground is cool so A/C won't run but humidity is high, etc. That's when additional dehumidification can really make a difference in comfort AND keeping mold/mildew away. Once mold gets started, it's a constant struggle to stop it and keep it stopped, and only controlling humidity can accomplish it.