The direct selection tool can select and drag an anchor point, but it cannot add an anchor point. The difference between the shaping tool and the direct selection tool is that the shaping tool has multiple functions of adding an anchor point and then deforming the line through this point, while the direct selection tool has multiple functions of changing the polyline angle into a flexible line angle. The other two functions are similar.

However, because the shaping tool wants to deform lines, it must add anchor points (unlike the anchor point tool, which can directly deform). If you want to deform polygons such as rectangles, you must first select a part with the direct selection tool and then work. In a word, I think this tool is clumsy and tasteless, and it can be cancelled completely. In order to achieve the same effect, direct selection tool, pen tool and anchor point tool can be used in combination at ordinary times, which can cover all the functions of plastic tools and be more flexible and fast.