Weeding otherwise bare and unused ground is no fun. Nor is weed whacking. Mulching inhibits future weed growth, but requires occasional replenishment. For many situations, ground cover plants are more practical. Once established, many sorts effectively exclude most weeds. Even more contain dust, and inhibit erosion of the surface of the soil below.
As the terminology implies, ground cover plants are simply plants that disperse laterally, over the surface of the ground. Many migrate by subterranean stems known as rhizomes, or by stems on the surface of the soil, known as stolons. Some are vines that behave like stolons. Also, many are merely prostrate shrubbery that does not stand upright very high.
Ground cover plants generally require more maintenance than mulch, and most want for some degree of irrigation. Conversely they require less effort than weeding. Furthermore, ground cover plants can live on slopes that are too steep for mulch to adhere to, and are more appealing than mulch. They might be as colorful or fragrant as other sorts of plants.
Prostrate shrubbery, such as creeping cultivars of juniper, manzanita and ceanothus, are best in areas that are big enough to accommodate their width at maturity. Within confined spaces, they need pruning around the edges, which exposes unappealingly bare interior stems. Prostrate shrubbery generally gets higher than other types of ground cover plants.
The many vines that work as ground cover probably stay lower than prostrate shrubbery, unless of course they climb into bigger shrubbery and trees. Algerian ivy and English ivy are famously aggressive if they overwhelm other vegetation. Also, they can cling to walls and ruin paint and siding. Star jasmine climbs too, but does not cling, and is more docile.
Perennial ground cover plants, such as various iceplant, trailing gazania, trailing African daisy and pigface (freeway iceplant), tend to stay lower than other types. Most require no grooming over their upper surface, so only need trimming around the edges. Scraps from trimming during winter can become cuttings for bare patches or elsewhere in the garden. Several types root efficiently.