This seems like yet another silly card for Luke Robinson. It's just one other tool that gives him absolute control over as much of the board as possible. Use his Gate Box to go away to his happy place, attach the Spiritual Echo to a location that you cannot (or may not want to) enter to eventually scoop up that last clue, deal with a nasty enemy, or whatever else his toolbox is capable of handling, bounce Spiritual Echo back to the hand to use again later on another nasty location.

Seems incredibly flexible [edit: especially now it's Fast]. You could slap one down on a location to investigate it later, double-tap a four-health enemy with Shrivelling for a single action or use it with an investigation spell (maybe Sixth Sense(4) due to the lack of charges) to basically give yourself an extra investigate every turn.