2) You want to hit a target 11-20 squares away from you. Most ranged attacks need to be within 10, and many need to be within 5, so in most cases this won't come up as 10 squares is already behind the rest of the party. But in certain campaigns, this could be useful.
3) You get granted a free basic attack (or are granted a bonus to your basic attacks). If you don't have acid orb that attack is wasted. However, for most parties, this won't come up much if at all (You can make it come up with itemization -- with, say, Eagle Eye Goggles or an Impaling Dagger. The latter is a bit cheesy.).