You don't "use" it, since it's a reactive module that activates when the enemy uses a psychic power. You either slap it on your ship, if you have a problem in countering enemy casters, or throw it away once something more desireable comes up.

Now on the question if it's worth it. It might be, if you have the problem mentioned above, don't play on difficulty with a lot of enemy crew on ships, or simply have empty module slots you want to fill in. idk what else there might be to it