Which tool is most suitable for cutting crescent shaped grooves into molding edges?

The most suitable tool for cutting crescent-shaped grooves into molding edges is the router. A router is specifically designed for creating various shapes and profiles in wood, including grooves, and is equipped with different bits that can shape edges in unique ways. When working with molding, a router can easily adjust the depth and width of the groove, allowing for precisely controlled cuts that enhance the aesthetic appeal of the molding by giving it a professional finish.

While other tools have their specific uses, they would not produce the same results for this particular task. A jigsaw is more suited for making intricate cuts and curves but lacks the precision needed for consistent grooves in molding. A table saw could be used for making straight cuts but cannot create the curved profiles required for crescent shapes. The plate or biscuit joiner, on the other hand, is primarily intended for creating joints between pieces of wood rather than for shaping edges. Therefore, the router stands out as the best choice for creating crescent-shaped grooves in molding edges.