The Knipex Pliers Wrench is best described in the US as a smooth-faced channel lock plier/wrench. Or, as a pliers-handled crescent wrench. I have a set of 3 different sizes and have used them for a year. They allow one to rapidly, safely and strongly grip nuts or bolt heads for tightening or loosening.
Rapidly: an adjustable crescent wrench is not rapid. One must adjust the opening to the nut or bolt head, and between tightening turns, in removing and replacing the wrench, inevitably the wrench loosens a bit and must be retightened. An open-ended or box wrench or socket is the best tool to use, but then one must keep in hand a range of sizes for each size of nut/head. In contrast the Knipex pliers wrench loosens and tightens like a pair of pliers or channel lock wrench.
Safely: an adjustable crescent wrench tends to loosen, rounding off the corners of the nut or bolt head. Pliers or vice-grips are worse, putting teeth-marks on the nut or head. In contrast the Knipex pliers wrench has flat, smooth, and parallel heads ensuring no rounding or gouging of the nut/head.
Strongly: the lever arm of the Knipex ensures a strong grip on the nut/head. I’ve used them to squeeze small solid aluminum rivets in building an experimental airplane.
To summarize, the Knipex pliers wrench combines the best features of other tools, enabling one to grip and turn nuts and bolts with a single tool, and apply considerable squeezing pressure on objects without gouging or tooth marks.