[legulere]

I guess it's just speculation because of the lack of any clues what they could be used for. You can only eliminate some possibilities, if they were used for food storage or people staying in there temporally you would find some rests of food on the ground, but they didn't.

[tcbawo]

I've always been amused that we tend to guess religious motives for ancient artifacts/places. Is there enough evidence to default to this where no practical uses can be found?