John Walton has various strategies to dissolve the conflict between Gen 1 and the scientific establishment. Indeed, he position suffers from overkill. On the one hand, he says God accommodated erroneous depictions of the world. On the other hand, he drives a wedge between functional and material origins. If Gen 1 is merely about functionality rather than materiality, then it can't conflict with mainstream science. If, however, God accommodates error, then why bother with the functional/material dichotomy?
Be that as it may, let's consider that dichotomy on its own terms. Were ancient worshippers really concerned with the functional value of shrines rather than the material value of shrines?
Fact is, it takes very little to discharge the functional value of a shrine. Consider numerous references to impromptu shrines in the OT, many forbidden, Take the Asherah pole. That's pretty modest. Or a particular tree under which to perform human sacrifice.
For that matter, compare the tabernacle to the temple. They were functionally equivalent. If functionality is the ultimate consideration, why the lavish outlay for the Solomonic temple?
Moreover, pagan civilizations build physically imposing shrines. Take Mesopotamian ziggurats and Mesoamerican pyramids. Or sprawling Egyptian temples–with their forest of columns. Take the Parthenon. The Temple of Artemis. The Pantheon. Vast Hindu and Buddhist temples.
These are designed to impress the viewer. A statement of wealth and power. If anything, functionality takes a backseat to materiality.