One of course is the price, the simple two or three dollars, hand-cranked ten dollars.
The second is the way of planing, simple is to rely on the hand to rotate the pencil to plane, if you have been hard to rotate, will continue to dig until the light pencil shape and the little secret pen knife, you know? The hand-cranked is a finite-position device, and relies on a crank to work, you will not work after planing.
The third is the effect of planing. The hand tip is relatively bald, good writing, and lead body more smooth, simple nib very sharp, easy to break.
Now the home is a hand-cranked, every day with a six-pencil to school, another pencil box to put a simple backup (small size).
If let the children themselves planing, hand-easier operation, the quality of the plane out of the average.