I love that point you made about dialogue having one role
Some of the roles of dialogue:
• Anchoring the story world (naming people, places, and situations).
• Communicating narrative causality (“why,” “how,” and “what next”).
• Enacting plot events (speech acts that themselves change the story—orders, confessions, revelations, deals).
• Revealing character (personality, status, desires, relationships, and especially subtext).
• Supporting realism (everyday texture and conversational rhythm).
• Shaping audience emotion and evaluation.
• Carrying thematic or authorial ideas, poetic/linguistic effects, or star-turn opportunities.