But an ellipsis is separate from and doesn't mmerge with sentence-terminal punctuation, whether its a period or somethig else (when it replaces words at the end of a sentence, the terminal punctuation follows the ellipsis, when at the beginning of a sentence that follows another, the ellipsis follows the punctuation.) The constructs you say can't be formed with it aren't needed.
Meanwhile there are a lot of languages and cultures. Somewhere all those characters were useful for something. My Atari had a very fun utility that gave you a compose-key that could combine just about everything on the keyboard to access all those weird characters of the extended ascii table. <compose>+ao would give you "a" with a ring on top (å), <compose>+ae gave the danish welded together character that I can't even type any more on windows.
The idea came from some unix thing I believe.