The problem isn't using it as evidence. The problem is that it is extremely likely that humans will use such evidence in much greater proportion than is actually statistically justified. If juries were perfect Bayesians this wouldn't be a problem.
Yes indeed. And the same goes, by the way, for other kinds of rational evidence that aren't acceptable as legal evidence (hearsay, flawed forensics, coerced confessions, etc).
This thread is for discussing anything that doesn't seem to deserve its own post.
If the resulting discussion becomes impractical to continue here, it means the topic is a promising candidate for its own thread.