mesh - Why does Unity's MeshCollider only use SharedMesh?

For components like MeshRenderer, Unity uses two references to mesh through script--mesh, and sharedMesh. My understanding as of yet that setting a "sharedMesh" will affect every GameObject that uses that component, whereas "mesh" alone will only affect a particular instance of that component. Same goes for "material" and "sharedMaterial".

However, for MeshCollider, the only thing available is "sharedMesh". The field "mesh" does not exist. I can work with this, but from a policy standpoint it seems very strange to me. Is there a reason that MeshCollider is treated differently?

I may be overlooking something obvious, but a Google search didn't help me.