Hello, Content Translation provides machine translation through Apertium and Apertium currently does not provide English to Hindi automatic translations. This is the case for many languages. In this situation the 'add translation' copies the text from the source language column (whether English or any other as per the selection made by the user) into the target language column, but with some modifications in the content like for instance the links. The links shown on the target column will be from the target language Wikipedia.
Since we rely on Apertium to provide automatic translations, we are unable to give any estimate on when they plan to make English-Hindi translations available. However, Urdu-Hindi is available and we will provide that in a few weeks. Even without machine translations, many languages have been using Content Translation's other feature to create new articles. We would like to request you to give it another try and let us know what could be done better to make it work well for Hindi. Since this is a beta-feature it is totally upto you to enable or disable it from your preferences. Thank you and do let us know how we can help.