A blockchain technical writer is someone who specializes in creating content related to blockchain technology. They have a deep understanding of how blockchain works and can effectively communicate complex concepts to a wide audience. As for the 15 features/advantages of a blockchain technical writer, here are some:

1. In-depth knowledge of blockchain technology

2. Ability to simplify complex concepts for non-technical readers

3. Strong research skills to stay updated with the latest developments in blockchain

4. Excellent writing and communication skills

5. Understanding of cryptography and security principles

6. Familiarity with different blockchain platforms and protocols

7. Ability to create engaging and informative content for various mediums (blogs, whitepapers, etc.)

8. Attention to detail to ensure accuracy in technical documentation

9. Collaboration skills to work with developers and subject matter experts

10. Ability to translate technical jargon into layman's terms

11. Proficiency in technical writing tools and software

12. Knowledge of regulatory and legal aspects related to blockchain

13. Understanding of blockchain use cases in different industries

14. Ability to create user-friendly documentation and guides

15. Adaptability to quickly learn and understand new blockchain technologies and concepts.