What exactly do the different settings on the Magnifica Evo do?

Seems odd, but I'm having a heck of a time finding out exactly what the various coffee settings on my Evo actually do. My machine has settings for Espresso, Coffee, Long, Americano, and Over Ice. The manual says how much water each uses, but not how it effects it or why you would use one over the other.

Are they all just pulling different amounts of water through the same amount of beans? Why would you want to do that? Wouldn't this just result in overextracted poor tasting coffee?