Due to numerous statements by Xiaomi representatives and insider information about the future flagship of Xiaomi Mi MIX 3 everything is already known before its official premiere. It has long been no secret that the front camera will be hidden in the shell-slider, but no one suspected that the mechanism of its extension would be manual.
The idea of a sliding panel with a front camera is far from exclusive, that's the way the OPPO clumsy went. But if it implements a motorized extension, the Xiaomi technologists decided to make the camera advance mode manual.
Perhaps in the company it was considered that the motorized mechanism has not the longest service life or greatly increases the cost of the smartphone, in any case, the gadget owners will have to independently advance the camera.