A gusseted bag has a seam that eliminates bulging, protruding corners. Gusseted bags create neat, squared bag ends. Although not required for earthbag building, they can reduce plastering work somewhat by creating flatter wall surfaces. Unfortunately, they’re not readily available in our area, so I just smack any protruding corners with a hammer or stitch them back out of the way with a 6d common nail.
If gusseted bags are available where you live, give them a try and let us know what you think.