What is clarified by adding “in the currency of such-and-such town” to “I owe one thousand”?

Degrees of Indication: Ẓāhir, Naṣṣ, Mufassar, Muḥkam and Obscure Expressions

• The due date necessarily becomes fixed
• It identifies the underlying cause of the debt
• It makes all currencies legally identical
• The currency of the thousand is specified