Is Sui decentralised?

Could you please elaborate on the question, "Is Sui decentralised?"? I'm interested in understanding the characteristics of Sui that contribute to its decentralisation, if any. Could you explain how Sui's architecture or governance structure supports decentralisation? Additionally, are there any specific features or mechanisms in Sui that promote a distributed and decentralised network? Furthermore, how does Sui's decentralisation compare to other blockchain projects in terms of scalability, security, and transaction speed? Finally, could you provide any insights into the challenges Sui may face in maintaining its decentralised nature as it continues to evolve and grow?