docs: highlight DeckRender workflow value

Author: AuntXue

README.md

@@ -1,8 +1,8 @@
 # DeckRender
 
-> Render any document format into visual artifacts.
+> One command from documents to pixels.
 
-DeckRender is a pure render engine. Give it a document, get back pixels — images, a PDF, or a video. Nothing else.
+DeckRender turns supported document and web inputs into images, PDFs, or videos through one predictable CLI and TypeScript contract. Use it to move visual document work out of one-off desktop steps and into repeatable software workflows.
 
 ```bash
 deckrender deck.pptx -o deck.png
@@ -12,6 +12,17 @@ deckrender deck.pptx -o deck.mp4
 
 It is to documents what `ffmpeg` is to media: one command, a small set of flags, predictable output. It deliberately does **not** parse content, extract text, or edit files — those belong to other tools in the [DeckFlow](https://github.com/deckflow) family.
 
+## Where it creates value
+
+- **Product previews and delivery** — turn document pages and slides into visual
+  artifacts that web and mobile products can display.
+- **AI vision pipelines** — create page or slide images for multimodal models
+  and document-understanding workflows.
+- **Automated publishing** — generate images, PDFs, or videos from scripts and
+  CI when the selected input/output route supports them.
+- **Review handoffs** — produce concrete visual artifacts that people or agents
+  can inspect before downstream delivery.
+
 ## Install
 
 ```bash