The comparison with predicates and adjectives supports the normal omission of wāw, but it does not prove that every circumstantial clause must lack wāw. A single-word ḥāl and a clausal ḥāl differ structurally.
When the circumstance is a whole clause, it has its own internal predication. Its external connection to the bearer of the circumstance must still be made clear, sometimes through a pronoun, sometimes through wāw, and sometimes through both.
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Appendix to Faṣl and Waṣl: Circumstantial Clauses, Wāw and Pronominal Linkage
The comparison with predicates and adjectives supports the normal omission of wāw, but it does not prove that every circumstantial clause must lack wāw. A single-word ḥāl and a clausal ḥāl differ structurally.
When the circumstance is a whole clause, it has its own internal predication. Its external connection to the bearer of the circumstance must still be made clear, sometimes through a pronoun, sometimes through wāw, and sometimes through both.