Quoted By:
Ally Switch could work for some mind games in doubles, provided you are fast enough to pull it off. Which Gardevoir and Gallade are usually not.
In triples, you could use it to switch from one of the outer sides to the other, which can help you with unfavorable positioning. Still very situational.
Memento is a last-ditch effort, but you might as well use Destiny Bond to be more productive.
They both suck.