The tool at the end of a robot arm, its gripper, determines which objects it can handle. Simple two-finger grippers suit uniform parts; suction works for flat, smooth surfaces; multi-fingered hands attempt the versatility of a human grip but are far harder to control.
Choosing a gripper is a trade between versatility and reliability. A specialised gripper does one job dependably, while a general one does many jobs less surely. Much of practical robotics is matching the hand to the task rather than seeking one hand for everything.