Telescopic forklifts basically have a pronged lift that comes over the top of the truck on a big crane / arm. It lets you lift the load a lot higher and have more control over where it goes at those heights, because you're moving the load on the end of the crane (called a telescopic boom). You can also move the load both away from and towards the forklift cab, which normal forklifts aren't able to do. Basically, what you're getting is height and versatility. The telescopic forklift is a popular tool in both agriculture and construction, where you often find situations where something with more control than a regular forklift is needed.