Rescue has a huge cooldown. To the point where even if someone does use it to abuse you, you can just shrug it off and move on. They can't continuously spam it, and if they keep doing it after every wipe you can just kick them from the party.

As a healer I like using Rescue especially during trials like Sophia. Or sometimes during certain dungeon mechanics. Do I need to do it? No. But they are stunned and about to get hit by the AoE.