A smart contract developer is someone who specializes in creating and implementing smart contracts on blockchain platforms. Smart contracts are self-executing contracts with the terms of the agreement directly written into code. As for the 15 features/advantages of a smart contract developer, here are some:

1. Expertise in programming languages: A smart contract developer is proficient in programming languages like Solidity, which is commonly used for Ethereum smart contracts.

2. Understanding of blockchain technology: They have a deep understanding of how blockchain works and its potential applications.

3. Security-focused mindset: Smart contract developers prioritize security to ensure that the code is robust and resistant to vulnerabilities.

4. Ability to write efficient and optimized code: They can write code that is efficient and minimizes gas costs on the blockchain.

5. Knowledge of decentralized applications (DApps): Smart contract developers are familiar with building DApps that interact with smart contracts.

6. Problem-solving skills: They possess strong problem-solving abilities to address any issues or bugs that may arise in the code.

7. Attention to detail: Smart contract developers pay close attention to detail to ensure accuracy and avoid any potential errors.

8. Familiarity with smart contract frameworks: They are well-versed in using frameworks like Truffle or Embark to streamline the development process.

9. Testing and debugging proficiency: Smart contract developers are skilled in testing and debugging code to ensure its functionality and reliability.

10. Collaboration and teamwork: They can work effectively in a team environment, collaborating with other developers and stakeholders.

11. Continuous learning: Smart contract developers stay updated with the latest advancements in blockchain technology and smart contract development.

12. Documentation skills: They can document the code and provide clear explanations for future reference.

13. Compliance knowledge: Smart contract developers understand the legal and regulatory requirements that may apply to smart contract development.

14. Communication skills: They can effectively communicate complex concepts to both technical and non-technical stakeholders.

15. Creativity and innovation: Smart contract developers bring creativity and innovation to their work, finding new ways to leverage smart contracts for various use cases.