A chaitya hall's long colonnaded interior was designed to support a specific devotional movement rather than static congregational seating: worshippers entered through the horseshoe shaped facade, proceeded along the central nave, and could then circle the stupa at the apsidal rear by passing down one side aisle, around behind the stupa, and back up the other, performing circumambulation, pradakshina, entirely under cover and within a single unified architectural space, a design solution not available to open air freestanding stupas. This function distinguishes the chaitya hall clearly from the vihara excavated alongside it at the same sites, which housed the resident monastic community and supported daily life and study rather than this specific processional form of collective devotion.
Before figural images of the Buddha became an accepted part of Buddhist art, the stupa at a chaitya hall's rear, unadorned by any human likeness, stood as the hall's entire devotional focus, and even after Buddha images became common elsewhere, many chaitya hall stupas retained this earlier aniconic form, or had Buddha images added to their facades only in later phases of a site's use. The horseshoe shaped window above the entrance, admitting a shaft of natural light that falls directly onto the stupa at certain times of day, was both a practical solution to lighting a windowless excavated hall and, quite plausibly, a considered part of the space's devotional effect, illuminating the hall's sacred focus in a way ordinary side windows could not have matched.