That's probably what they did for v1.0 after they saw it is not that easy to zoom such that the whole paragraph always fits into the visible area.

Where to center to is only one vector, the other is how much to zoom: ideally it’s such that the text block fits on the screen. But again, that requires knowing the bounds of the text block. Zooming by a constant wherever you tap is a much less useful feature for text (vs. a map for instance), but I think it’s what we defaulted to (can’t remember if it was that of just nothing).