Originally Posted by cool brew
It's actually a good idea to get some of the malt extract in with the grains to help convert any of the grains that are enzyme free. Depends on what you are going for, but you definitely want to convert a good amount of that extra starch into sugar.
Um, not to nitpick, but steeping grains is steeping grains, and mashing is mashing. You might pick up some extra sugar from steeping, but that's not the purpose. Steeping is for flavor and color. If you're looking to convert starches into sugars, then you mash. If you convert too much of those starches into sugars, you'll end up raising your OG, which can adversely affect your final product if you're not aware of it and don't adjust your hop bill accordingly.