It can also be used on a firm, level, adequately ventilated bed base that supports the whole shikibuton. Check the underside regularly and lift the bedding so moisture can escape; a bed frame does not remove the need for airing.
If you are comparing Japanese futon care with a conventional mattress, focus on airflow, dryness, regular turning, and the right cover; these habits help the shikibuton keep its shape and comfort.