It depends on how complicated of an animation you need to do. For example a very simple moving the belt thru the buckle can be done with a curve and a curve modifier or a lattice with lattice modifier and move the object in a straight line along the curve/lattice. Side Note: Both curves and lattices have shape keys. Be aware that the shape keys move in shortest direct lines. If you need something more complex then a splineIK rig is the route I’d go. Here is a video to help with that. https://www.youtube.com/watch?v=K9uDM1lHm28&t=64s Even though it’s common in Blender community to use empties for the hooks. I personally recommend using bones for the hooks. In the video if you made a copy of the bone chain used for the Spline IK that will put the bones in the best position. The in edit or pose mode select the bone. Then in object mode select armature, shift+select curve, tab into edit mode, select the control point, and press ctrl+H->hook to selected object bone. Repeat for next hook. You can disconnect the hooked bones if you need more wild movements. Some riggers would just use one bone chain and use a regular IK setup. It really depends on the animator’s animation style in my opinion.
