A structured summary is an explanation, not an extraction. It gives your material hierarchy and shows how its important parts relate.
Why a transcript is not enough
Transcripts are valuable sources, but they preserve the order of speech rather than the order of meaning. Arcs reads across the complete material to surface the point, supporting ideas, decisions, tensions and details that deserve to remain visible.
Built for different kinds of source
The same need appears in a meeting, a private journal, a work file and a rambling voice note: you want to know what it means without flattening what made it yours. Arcs keeps the original source available in Notes while Read gives it form.
A beginning, not an endpoint
The summary establishes the whole. Threads lets you open the topics inside it. Next helps you decide what deserves further thought. Build can turn the understanding into an argued presentation.