In Khamsin, The Devil Wind of The Nile, this ancient instrument is described as being used for worship as well as entertainment.
With expectant stillness at its height, [the High Priest of Ptah] intoned the old sacred chants, his rich baritone echoed by the pure high voices of his temple chantresses. The simple notes of a lonely flute rang out, a harp adding its melodic strings.
Sistrum-players rattled their papyrus stems. The beat quickened. With nothing more than belts around slim waists, the undulating chantresses mesmerized the crowd; it often fell to these lithe servants of the gods to keep the beer-drowsed audience alert.