I use this stitch selection for bar tacks all the time. I don't lower the feed dogs for this. When I make a obw, or stack and whack, I pin the layers, then bar tack the whole thing. I cut the pieces on my accucut so this way I don't need to worry about the blades hitting a pin. I really think that it keeps the layers from shifing, and it's easy to clip the tack when you start piecing.