What is Cardano used for?

Excuse me, could you please elaborate on the various uses of Cardano? I'm quite curious to understand the breadth of its applications in the realm of cryptocurrency and finance. As I understand, Cardano is a blockchain platform, but I'm interested in knowing how it specifically facilitates transactions, governance, and potentially even smart contracts. Additionally, could you discuss its sustainability features and the role of its native token, ADA, in all these applications? Your insights would greatly enhance my understanding of this emerging technology. Thank you in advance for your detailed response.