docs: punch up AI second brain intro in README

Author: juanceresa

README.md

@@ -4,7 +4,7 @@
 
 No code, no database, no infrastructure — just a CLI and your documents. Drop in PDFs, papers, articles, or records — get a browsable knowledge graph that shows how everything connects, in minutes. sift-kg extracts entities and relationships via LLM, deduplicates with your approval, and generates an interactive viewer you can explore in your browser. Concept maps for anything, at your fingertips.
 
-Building an AI second brain? [**sift-kg is the knowledge graph you build in 2 minutes instead of 2 years.**](#ai-knowledge-base) No manual linking, no tags, no folder hierarchies — just point at your stuff and get a structured graph your agents can operate from.
+Everyone's building AI second brains in Notion and Obsidian. Who has time for that? [**sift-kg is the knowledge graph you build in 2 minutes instead of 2 years.**](#ai-knowledge-base) Just point at your docs and your AI has a structured understanding of how everything connects.
 
 **[Live demos →](https://juanceresa.github.io/sift-kg/)** graphs generated entirely by sift-kg