I haven't seen convincing evidence that vitamin D supplementation is materially useful for anything but rickets. I get the impression that naturally high serum

I haven't seen convincing evidence that vitamin D supplementation is materially useful for anything but rickets. I get the impression that naturally high serum levels are an effect rather than a cause of other positive things, and that supplementation mostly increases serum levels without effecting positive things. It doesn't seem harmful either, so can't hurt might help?