In a regular 10-fingers typing position on the middle row (asdf and so on), when I extend my right little finger to the right in order to hit the Return key, its tip is naturally positioned on the row above the middle row. Thus, I only comfortably hit the Return key exactly because it extends upwards. Conversely, any time I use a keyboard with a low Return key, I frequently unintentionally add a backslash or whatever character is mapped to the key above the low Return key when I'm actually trying to add a linebreak or close a dialog box.