It really does help!
Storyboards are useful because it helps visualise the entire movie length into a little comic book. I found that without planning my movie beforehand, and just making stuff up as I went along (like I did with DE_dust, and DE_aztec), I tend to lose focus of the objective, or what I really wanted the audience to see. With a storyboard planned with all the twists and turns of the movie; I can see more clearly which scenes will work best and I can spot potential flaws early on. The earlier you spot the potential problems you are to encounter the better. I know for a fact that, if I spent ages on a scene only to find that it didn't work as well as I wanted it to, I'd be too frustrated to throw all that work away. When that happens and you keep the scene, you know you've been defeated by your own dignity.
Since DE_dust2 is a pretty big project, that lasts 6 minutes long, I know that I'm bound to lose track of what I'm doing. It gets pretty confusing when I have to deal with 13 characters (and a chicken!), as well as make sure the plot goes accordingly. So I spent a good week or two planning my storyboard. The 10 sheets of storyboard I drew up are always on my desk, reminding me to work on it (motivation!) and also to steer me back to the right direction.
Storyboard Images!

As you can see, from my beautiful drawings (lol), it isn't incredibly detailed. Its the idea and mise en scene(fancy word for what you see on screen) that counts.. You may also notice some blanks or panels that aren't filled in, thats because I was having trouble making up my mind. There is also the scene with Dumbass and Lagger that I changed altogether when I did the final animation as I felt it was a better idea.