Question on the Overhand Shuffle

[RyanMagician]

Hi everyone! I was recently reading Card College Vol. 1, and I came across the overhand shuffle section. I noticed that it said the right hand should not move up and down, but in an arc. I have never done it like this. Is this an important detail? What do you do.
Thanks!

 

[RealityOne]

Without looking at the description, it seems that moving in an arc is more of a wrist movement than an arm movement. I move in an arc.