Looks like you still have to carefully match the cut edges every few inches as you draw the strip through the roller, so all it essentially does is crease the seam, vs using an iron to press it.
The fabric strip goes evenly in it much better than I expected, and I wasn't all that careful about feeding it through. Not having to use the iron to get a sharp crease is what I like about it.. it wasn't expensive so I thought I'd give it a try. My quilting friend said it was hard to find one to buy now. it's sold out everywhere.