I remembered I had written something like that when I made the Scallop Template script, but I dialed it down to only sharp corners, because it seemed silly to put a scallop in the middle of a rounded segment. I have now updated scallopTemplate.js with the option to draw a circle around sharp corners only, or around all anchor points.
If you have a line graph, you can use scallopTemplate to drop circles over the anchors like this:
If you then ungroup the circle objects, you can then use copyToMultipleObjects to replace the circles with whatever object suits your fancy...
If for some reason, you don't like the extra click, and plan to only use one or the other, you can edit line 26 of the script from:
var selectAll = confirm("Scallop corners only?");
var selectAll = true;