Functionally, it's just a pair of high tech hiking staffs. Some are adjustable in length; some are fixed length (just like a stick one picks up upon entry into the forest for use as a hiking staff).
They are typically made out of aluminum or carbon fiber and so are lighter than a wooden hiking staff. They typically come with padded handles/grips and many (other than the UL carbon-fiber ones which really don't require them) come with a wrist strap for supporting the wrist so that one doesn't have to grip tightly when using them.
They can be used without any kind of "basket" (sort of a slightly rounded circular disk or plate near the bottom) on some terrain, but often on muddy or rocky terrain a "basket" is placed 2"-3" above the tip to prevent the tip of the pole from sinking deeply in mud, or jamming into crevices in rocks. In snow, larger diameter baskets are used.
Tips are generally made of carbide so that the poles grip many types of surfaces, though some people prefer to use rubber tips to avoid damage to rocks, lichens, plants, etc. as well as to reduce damage to the trail surface.
Some people like to use just one, most people use them in pairs.
They help to transfer some of the work done by the muscle groups of the lower body to the upper body and so reduce long term fatigue of the muscles of the lower body, enabling one to hike either faster, farther, or both.
Furthermore, they greatly assist in balance on difficult terrain, as well as ascents, and reduce shock to the knee joints on descents.
But if you currently use a hiking staff, you are familiar with these benefits already.
Some people use them for double duty and use them to pitch their tarp or tarptent style shelter at the end of the day.