To add to Spinebot's answer, Spine doesn't provide a complete physics engine with collision and other advanced feature, it provides only lightweight physics needed for animations.
If you want your Spine skeleton to affect your game toolkit physics, you can have a game toolkit physics body follow a Spine bone.
Or to go the other way, you can update a Spine bone using your game toolkit's physics body. This can be used to ragdoll your Spine skeleton or have skeleton parts respond to game physics.