One of the main things that make polished concrete a preferred flooring method is its thermal mass property, which allows it to absorb heat fast but release it slowly. Therefore, if the floor absorbs heat during the day, you do not have to worry about it being cold at night.
This applies mostly in winter. If there is a heat source in the house and the floor absorbs that heat, it will still be present at night.
Also, during the summer, when the floor absorbs the coolness of the room at night, it will still be cool the following day.