This would also allow more data to be crammed onto the screen
"more data onto the screen"
But ignoring the fact that you really did say that, you are aware of alternating sublines right? They can already alternate the data on the screen without scrolling sideways, and this request is simply described as a way of animating the transition between sublines.
It doesn't allow anything new to be done in terms of information, it's just described as changing how an existing transition would display.