When you use Markdown with purpose in a prompt, you communicate at two levels: what you want, and how you want the AI to think about it. That second level is meta-communication, and most people never use it.
See the difference
Without structure
Can you review my code and tell me what's wrong and suggest improvements and check for security issues?
With purposeful Markdown
**Review my code:**
1. Bugs and errors
2. Suggested improvements
3. Security issues