It only works if you have someone in the need for a rescue to a slow-ish mechanic.
Cause like so many things in FFXIV Rescue is just dogshit and will only rescue you from a mechanic if you "arrived at your new location" which most of the time will result in them getting hit with the mechanic you try to rescue them from anyways.

So, to give an example, the only good place that comes ot mind right now would be Arcadions 12th fight, the arm mechanic.
But tbh if its not your first time and you don't do an obvious "arm here, you not here, or bad stuff" I most likely won't bother rescuing anyways.