Keyboards like that appear to be made in a more compact manner for smaller spaces requiring the use of a keyboard. If you notice, in that example you found, it is more pushed in as a whole on the right side in. It just seems to be for convenience if everything else. Also, some people type differently, have smaller hands, etc., so a smaller keyboard works better for them.
In my opinion, the " | and \ " button is in the way of the backspace button (seen on the picture) and the Enter Button is large.
its a trade off. Either you have a long backspace key or you have longer shift keys. On my keyboard, I have a long backspace key, and the |\ key is to the right of the left shift key, which is half the length of the one in the picture.
Both my shift keys and the backspace key are the same length and look to be around 1 and 1/2 inches to 2 inches (don't feel like converting that to cm), the space bar is also fairly large being around 5 inches long by about 1 inch tall. I'd get a picture, but I'm lazy. Also, if you were just referring to keyboards like the one pictured, I suppose my comment can be omitted.
Do many keyboards in China have small backspace keys... Anyways, If you have a small backspace key, you probably have a large "L" shaped Enter Key. On my dad's keyboard, the Shift key on the right side is smaller than the one on the left. My mom's laptop's keyboard has a small shift key on the left.
My keyboard has a small bs key. But is also has a somewhat jacked up special key lineup. (home/end, others keys like that) Looks like this... 00 0 0 0 0