That stuff creeps me out a little bit, though I guess it's basically peanut butter with the oil removed. My mom has some similar stuff in her food storage, since the fat is removed it is more shelf stable. I have used it before in oatmeal, but I wasn't crazy about it. I like having a bit of fat in my oatmeal, it helps keep me full longer. Really the only other thing I use peanut butter for is PBJ's, and I don't think I'd use PB2 for those because texture matters more than in oatmeal or something.
As far as adding sugar, most regular pb has sugar added. Natural peanut butter doesn't though.