in regards to sewing with a handcrank...
With an electric machine or treadle most folks use one hand in front, and one hand behind the stitch. You have NO feel for the "pull" that the machine has, that is why folks use the second hand, to gain that control.
With a handcrank each rotation of the handcrank cycles the machine 3 times. You can literally feel in your right hand the feed dogs pulling the fabric through. You only need your left hand to steer and provide some resistance to the pull. You have WAY more precise control of stitch location. I have yet to find a person who does not find hand crank sewing easier than electric or treadle, once they have practiced it a bit.