Is YFI built on Ethereum?

Excuse me, could you please clarify for me if Yearn.finance's YFI token is indeed built on the Ethereum blockchain? I've heard a lot about its decentralized finance capabilities and I'm just trying to get a better understanding of its underlying technology. If YFI is indeed based on Ethereum, could you also explain why that was chosen as the platform for its development? I'm quite intrigued by the potential benefits that come with leveraging Ethereum's robust infrastructure and ecosystem. Thank you in advance for your insights.