Comment by ladberg

It might output a much more detailed image than a human-drawn sketch which could be less useful or more damaging than the vague sketch.

Imagine that a police officer is looking for someone matching the image but doesn't know that it's hallucinated from a vague description, they could let the real suspect go or incorrectly arrest someone who happens to look like the AI generated image but otherwise doesn't have any reason to be a suspect.

Police are already greatly overestimating the accuracy of their own facial recognition tools because they don't realize the limits of the technology, and this would just be worse.