Temple prostitutes were prevalent in a number of "pagan" religions, especially in the middle east. For instance, the religion of Mesopotamia (whose name I forget, but which is mentioned in Snow Crash) has temple prostitutes.

These temples were equal opportunity employers, as there were both male and female prostitutes.

Temple prostitutes have fallen out of style in recent times, most likely due to the efforts of christian conquerors. When they were in vogue, they probably helped to increase attendance, along with whatever religious purpose they served.

In ancient Greece most temples of Aphrodite had a brothel in the vicinity. The women that inhabited those places (commonly knon as hetairai) were considered to be priestesses of the Goddess.

In fact the prohibition of homosexuality in the jewish (and therefore later christian and moslim) bible as it appears on Leviticus (18:22) derives from the existance of such male-priests in the middle east (known also as Kedeshim), the word used to discribe the reason for this prohibition- To'eva (cf.) seems to strengthen this theory.

Temple prostitutes devoted to Baal, the Canaanite god of fertility, did indeed serve a purpose other than keeping attendance high at their temples. The devotees of Baal believed their orgiastic practices would arouse him and result in rainfall, which was thought to be his seed pouring down from heaven. One reason the Hebrew people seem to have had a hard time staying away from these prostitutes is that they may have been afraid that Canaan was not the land of their god Yahweh and therefore he would not be able to protect them from drought and crop failure. So they wanted to please the native god of the land that he might allow their crops and animals to thrive.