Scrolling jerky when 1 column is selected

When I set it to "1", it jumps at least a page at a time. Is that expected behavior? 

How are you changing position in the book?

In paged mode (which effectively is what settings columns to anything other that None provides) then pressing the left/right button at the bottom of the pane will move a page at a time.

If you want a different effect, you can choose one of the options in dropdown menu at the top (you need the Locator Bar showing to see this) and then use the up / down arrows to change position

I'm using a trackpad to scroll.

Yes, that will move a page at a time.

BTW, the reason I want the column set to "1" instead of "none" is that I can view footnotes at the bottom of a page when it's set to "1". 

I understand - but you will need to use the arrows in the locator bar to change position other than a page at a time.

I can use my trackpad to scroll smoothly a verse at a time when the columns are set to "none." Why can't I do that when the columns are set to "1"? 

Because the default action when columns are set to 1 is to move a page at a time

The what's the point of having the option to select "verse" if it always moves a page at a time? 

The verse option allows you to move up / down a verse at a time but only by clicking the up / down arrows in the locator bar.

It can't be controlled by using the scrolling motion of the trackpad.