actually, the streaks add to the realism. in most toasters you have heating elements set vertically an inch or two apart and the bread is set down within those elements. as the bread toasts, those places where the elements are are slightly hotter, thus toasting the bread a little bit more and making that area a little bit darker. so, the streaks work for me
i think it's an effect filter because he/she wanted the transparency showing and not a background image, thus you have to include the image component to do that, ergo, effect filter rather than texture.
If wishes were horses... there'd be a whole lot of horse crap to clean up!
Craig