Both explanatory apposition and substitution may appear without a conjunction. So the mere absence of a connecting particle does not make them identical.
ConstructionCharacteristic focus
ʿAṭf al-bayānClarifies the referent of the first expression
BadalReorients and reinforces the intended grammatical target
Naming which friend is meant chiefly serves clarification. Saying “most of them” after “the people” redirects the exact range of predication and exemplifies substitution. Their benefits overlap but should not be collapsed.