Maybe they mean the tension is adjusted correctly and the material feeds through pretty straight? I totally agree with Candace. I've seen some real nice straight stitch machines. A good argument for a ss machine - think about it 99% of the time you are sewing straight stitches. Recently a woman bought a machine from me - the straight stitch machine was cheaper than taking her high end Viking/bernina/Janome (I forget) to be cleaned ONE time.