وكذلك السفر لما أقيم مقام المشقة في حق الرخصة.
Travel is treated as a proxy for hardship in the law of concessions.
Actual hardship varies among travelers and circumstances. If each instance of shortened prayer or the concession not to fast depended on a fresh measurement of subjective strain, the rule would be unstable. Qualifying travel is therefore used as an observable legal marker for particular concessions.
The doctrine does not say every traveler experiences equal hardship. It substitutes a defined outward circumstance for variable inward hardship within the specific scope of the concession.