It’s not a throw-the-book-at-the-wall type of sin, but it can be annoying. The biggest difference is that where an ellipsis character is stable with three periods this can happen:
If you look very closely you can see the difference. Despite being an actual character, it looks like three periods. In Word, and especially in Word docs being formatted for either ebooks or print-on-demand editions, ellipses can be troublemakers. This isn’t a grammar blog so for information on how to use ellipses, here’s a pretty good article.
