The term religious laws and rulings signals that the normative status of an action is established through the guidance of the Sharīʿah. Obligations, fasting rules and conditions for transactions do not arise merely from an individual's preference or a casual guess.
Reason helps interpret legal expressions and apply principles, but claiming that something is a divine legal requirement calls for defensible evidence. Juristic reasoning must therefore attend both to transmitted sources and to understanding their implications.
We should distinguish explaining a ruling's wisdom from establishing the ruling itself. An expected benefit alone does not automatically make a particular act obligatory or prohibited.