Just another simple observatory, similar to dozens around the globe, made with clever artifice and ingenuity. And the reason always proffered for these unique astrological platforms? Why, so that the primitives would know the precise instant in which to drop a seed in a stick-scratched furrow in the ground. Yep, star alignments, geophysical constructs, and enduring monuments all brought together for the simple folk to plant some crops.
Despite the wonderful arguments for such an august objective, wouldn't a couple of sticks in the ground have sufficed, or a stone on the ground that captured a shadow of another edifice twice a year have been sufficient?
Maybe I'm jaded, but that seems to evince a lot of brain power for crop planting, evincing a tad bit of overkill to farm and till and harvest a field.