For a household mirror, the main thing is to preserve the reflective coating from mechanical damage, so the amalgam is applied to the back surface of the glass. The astronomical mirror should not have additional optical parts, on which the luminous flux is lost and the image is distorted. Therefore, a reflective coating is applied to the mirror surface facing the light rays.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.