Too few keys. It'll become a major pain if you type a lot. Every number or punctuation requires holding another key. Yet it does not have proper thumb key.
This keyboard is impossible for use for Chinese, Russian, French. For example, to type Chinese with pinyin, every ~4 keystrokes you need to press number key. It just becomes painful here. For Russian, French, you really need lots more keys.
〔►see Chinese Input Methods〕
〔►see Russian Keyboard Layout〕
〔►see German Keyboard Layout〕
〔►see French Keyboard Layout〕
similar is Atreus Keyboard
But if you are a programer, typing English, does not work long hours, or need a keyboard on the go, i think this one is superb. Extremely well designed in tech, and comes with a innovative pointer, and is beautiful.