Causal linkage and reinforcement are not the same test

The Predicate as a Single Expression: Causal Linkage, Clauses, Verbs and Nouns

There are two separate tests: does the predicate concern someone connected with the main subject, and does the construction heighten the force of predication? A causally linked assertion need not be chosen to strengthen the judgment; a non-causal clause can have that strengthening effect.

ExpressionCausal linkageReinforcement
زَيْدٌ قَائِمٌNoNot structurally required
زَيْدٌ قَامَNo; the action is Zayd'sPossible through a verbal-clause predicate
زَيْدٌ قَامَ أَبُوهُYesIts defining feature here is causal linkage

The predicates “causal” and “strong” are not interchangeable terms.