Why is Kusama so popular?

Can you explain why Kusama has gained such widespread popularity in the world of cryptocurrency and blockchain technology? What are the key factors that have contributed to its success, and how does it stand out from other similar platforms? Are there any unique features or advantages that Kusama offers that make it particularly appealing to users and developers? Additionally, what are some potential challenges or limitations that Kusama may face in the future, and how is the team addressing these issues to ensure the platform's continued growth and success?