@MereDintofPandiculation - I suspect that you are correct in that the flowers have a different odour, depending upon one's perception; to me they smell very pungent and acidic, as does the bark and sap and, yes, although the flowers can be eaten in the form of fritters, that is one delicacy I will pass on!
Many superstions attached to Elder, some good, some bad - bad luck to bring it indoors or to burn the timber, but, on the other hand, growing near to a dwelling it is said to deter the devil and, like Rowan, also witches.
And, of course, it is beloved by blackfly and aphids, so I suppose, it could be used to lure those pests away from more desireable plants.
I agree that Cercis is another tree from which, legend has it, Judas hanged himself - one of many, who knows where the truth lies?