The latest patch introduced a "Reset Quests" option which seems to clear all quest progress and restart the campaign. However, I have it available on some characters and not others. Also, I'm not entirely clear on how this is different than simply changing which quest or act I'm on and setting it back to the beginning of Act 1, other than the fact that it wipes all other progress.
What exactly does Reset Quests do and why would I want to use it rather than just changing my progress point back to the beginning of Act 1?