What most fundamentally distinguishes khabar from inshāʾ?

Inshāʾ: Requestive and Non-requestive Forms, Imperative Constructions and Rhetorical Functions

• Khabar makes a truth-evaluable claim; inshāʾ directly performs a request or other non-assertive act
• Khabar must always use the past tense
• Inshāʾ consists of only one word
• Inshāʾ cannot express a question