Ground-covers plants have a range of attributes, they can suppress, even eliminate weeds in the garden, acting as a natural mulch in the garden. They can provide root cooling to more substantial plants. They can cover an area quickly, often in areas which other plants struggle to grow in, such as steep slopes and gullies.
Many online plants ground-covers are self-puckering, so as they grow, the limbs root into the ground, effectively creating another plant. In this way, the one original plant can spread and ramble on for a long distance.