I was taught (Canadian university, early 1990s) that ellipses were to replace missing passages of words such as within very long lists, and never to indicate a pause. In fact, I was docked marks for using an ellipse to create a pause. There were even distinctions for correct usage between three-period ellipses and four-period ellipses. If the ellipses came at the end of a sentence, it was necessary to include a period, something no one seems to do these days. I was also taught that emdashes --- or three hyphens when there was a possibility of formatting inconsistencies between different computer word processors --- were used for certain types of parenthetical clauses. Abrupt closing breaks were indicated by endashes or two hyphens.

I don't always like stylistic devices and they are inappropriately used, not to mentioned overused too often, but I've come across two examples of that full-period stop which were so effective that I set aside the usual reaction to its unorthodox usage. I've also come across a handful of examples of incomplete clauses used as full sentences which had a very powerful impact. Admittedly, the exceptions are rare and the overuse lessens the effect.