I am missing two possibilities. In English Wikipedia, this tool is not working, but why it cannot be used to translate something to sandbox. I would also appreciate to translate some texts, which are not going to be saved. I am talking here about the literature I use. E.g. Google Translate is very bad in translating from German, but this translator is good. Could it be that you enable some randomm translation of the pieceses of text (like Google Translate) do which wont be saved?
By the way, why I cannot use it on en.wp even I have extend confirmend flag there?