The Game Bone deformation is very similar to the Bone deformation and allows you to create a skeleton structure in which the parent bone moves the child bone. The difference is that the Game Bone deformation is optimized to export to game engines, mainly Unity.
The Game Bone deformation is mostly used when animating the extremities of a character, such as the arms or legs, adding fluidity and a natural feel to the animation. The Game Bone deformation can be manipulated to rotate a limb at an articulation joint and to shorten or elongate the extremities of a limb. It's also quite useful for bending the torso.
The main difference