Should I have my child practice pinching and using scissors?

Rather than jumping into hard practice, start with foundational play. Pinching strength develops naturally through the experience of grasping objects of various sizes, shapes, and materials. Scissors are even more complex, so first do play that moves the fingers individually and play that coordinates both hands. Once the foundation is there, move gradually to spring-loaded children's scissors. Rather than "it's dangerous, so I won't let them use it," give them the experience in a safe environment.