If rain falls from the roof because there are no gutters, the water causes massive erosion, dragging more and more dirt away every time it rains. This causes the carefully sloped landscape to wear away, allowing runoff to flow into your home instead of away from it. Erosion also causes the base to settle. Gutters remove water from the foundation of your home.
The foundation walls remain dry and intact when the gutters work. With a basement, most Michigan homes have basements, and the stagnant water next to the foundation weakens it to the point where you may need a serious and expensive foundation repair.