Improv is more than just spitting out a bunch of funny stuff that's unrelated to the material. You have to stay in character, you have to react and respond as the character you're trying to play. You have to service the story, and I think improv training has helped with my listening, responding, and my audition technique. It's sounds so silly, but it's true. Because not only do you improvise during the audition, but once you get the part, they'll say, "Throw away everything. Just improv this scene. Do whatever you want." Someone could panic if they're not used to doing something like that.