Eaiser dragging and gestures I guess. But I think a lot of it is aesthetics. Apple keeps the same aspect ratio pad and then increases the size so it always fill

Eaiser dragging and gestures I guess. But I think a lot of it is aesthetics. Apple keeps the same aspect ratio pad and then increases the size so it always fills the space between the keyboard and the edge of the laptop. So as screen size increases so does the trackpad. It does look better than when they didn't do this for example the old 17" MBP which IIRC had the same trackpad as the 13" at the time.