Is copilot function can use in excel cell gone?

https://support.microsoft.com/ko-kr/office/copilot-%ED%95%A8%EC%88%98-5849821b-755d-4030-a38b-9e20be0cbf62

with that page, I upgrade my 365 to 365 premium. But there's no =COPILOT()

What the hack? I just threw away my money?