more than a page turn?

I find the continual swiping distracting. And it's a much more complex motion (akin to a page turn) and must be done more frequently than paing. A tap of the space bar is about the simplest motion, and (except in cases of bad page design) gives a clean "start at top for next page" rather than trying to figure out where on the screen your next line is.

Preferences vary, obviously.

Yes, a page turn with a book gives you a very specific place to continue. Spacebar or page down doesn't.