Notice that “strong field” is not synonymous with Planck-scale physics in this context. In fact, a stationary black hole
would not serve as a probe of the strong field, even if one were to somehow acquire information about the gravitational
potential close to the singularity. This is because any such observation would necessarily be lacking information about the
dynamical sector of the gravitational interaction. Planck- scale physics is perhaps more closely related to strong-curvature
physics.