I first thought, "Does anyone really need another xyzOps buzzword ??"
But I think this one really makes sense. It's all about cloud financial management. By bringing financial accountability to teams with the cloud's variable cost model, you enable them to make business tradeoffs between speed, cost and quality.
It's not primarily about saving money, it's about making money.
FinOps is about removing barriers, empowering development teams to deliver better features, applications and migrations faster, and enabling cross-functional discussion about where and when to invest. Sometimes a company will decide to tighten its belt; sometimes it will decide to invest more. But now teams know why they're making those decisions.