What's the difference between BoxHelper and Box3Helper?

BoxHelper “uses Box3.setFromObject to calculate the dimensions”, so I feel that it just requires creating one less box3, if I want to present a mesh.
I wonder what are the specific use cases for them.
BoxHelper.update() is so clear in the document, while I still haven’t figure out how to update the Box3Helper. I guess it’s Box3Helper.updateMatrixWorld() but can’t find any example.

Like mentioned in the documentation, Box3Helper is intended to visualize an instance of Box3 which is essentially an AABB.

BoxHelper instead is intended for instances of Object3D that have a geometry assigned. The helper visualized the corresponding AABB.

Yes, the code is somewhat redundant. If you work primarily with objects, use BoxHelper.