That is the standard (European) ISO layout for keyboards, it is common across different locales and brands. Arguably the US is the outlier here (again). The obvious advantage is the extra key it provides. While the enter key placement/shape might be debatable, I'd argue that the the left shift key reduction is purely advantageous. The shift key is still well sized (bigger than normal key) and easy to hit (the pinky movement is nicely symmetrical with right shift), and the keyboard gains space for one extra key (always useful).