Copying function, not just form
Bio-inspired robotics is the practice of studying a mechanism that evolution has already refined, an animal's gait, a plant's growth pattern, an insect's flight, and adapting the underlying principle to solve an engineering problem. The key word is principle. A robot shaped like a spider isn't automatically bio-inspired if the resemblance is only cosmetic. What counts is when engineers identify why a biological structure works so well, the geometry of a gecko's toe pads or the wing kinematics of a hoverfly, and carry that specific mechanism into a design that performs better because of it.
This distinction matters because nature is under no obligation to be efficient or elegant, it's simply constrained by what survives. Sometimes those constraints produce solutions that are also excellent engineering: a fish's body shape that minimizes drag, or an ant colony's decentralized coordination that scales without a central controller. Bio-inspired design is the discipline of recognizing which biological solutions actually transfer to hardware and control problems, and which are just interesting to look at.