Your datura story is so good. Sometimes it is just best to leave something alone even though there are some good things about it. But now there are lovely commercial varieties which are surely tempting.
My neighbor pointed out a large weed which he called jimson weed. I started to pull it up and he said, "Don't do that; I have a friend who would appreciate the seeds." So I didn't. Now I have these large, ugly seedling leaves all over the area where the plant was.