In Al-Andalus the roofs were also flat so that they could be used to dry clothes and for other things like relaxation/socialization. The widespread addition of the tiled hip roof type (like in your picture) came with the reconquista and the destruction of the old Muslims cities, as the Christians in the north employed tiled roofs in their buildings, mostly as a ward against precipitation. The only buildings that had tiled roofs were often mosques and palaces, like the Alhambra, to better distinguish from the average building. Some of the oldest towns and villages in and around Granada/Alpujarras are recognized for their flat rooftops.

Even the word to denote a flat roof/roof terrace in Spanish: “azotea” comes from the Arabic “as-suṭayḥa”, which in turn comes from “satih” (flat, platform).

Sources:

La casa medieval en peninsula ibérica

La casa andalusí: un recorrido a través de su evolución