I scroll/swipe left or right with my thumb, most of my use is reading comics or watching videos, video being where the resolution most matters doesn't really require much interaction at all.

As far as typing I hardly look at the screen then and ppi don't really matter then. If I am just checking my notifications it barely comes out of my pocket. But when we are in a discussion of ppi being useful, I assume we are talking about the uses where you are actually looking at the screen.

Edit: Just realized that when I type longer messages or emails I tend to hold it 2 handed landscape and hold it pretty close(around 1 foot away) and tap it out with my thumbs because I find it more accurate. So I guess that is how one would type with it that close.