This is a story skip. Many forms of character progress in FFXIV are gated by that individual character completing the main storyline quests.

A story skip boosts the character to the beginning of the current expansion tier, so it is not possible to use this mechanic to compete with standard players on current content. I think the intended use case is alt characters (which are less necessary in FFXIV because you can play all jobs on one character, but many players still have them).