Emojis are useful as visual indicators, there's anything from flags to check marks in them.

They can be super helpful to decorate CLI output.

If it feels juvenile but is helpful (as in many cases is) good.

Sure, some CLIs may over do with rockets and such, but any tools can misused.

I want country codes not flags. And check marks do not require emoji.

Every emoji I saw in a terminal or Git commit message was worse than alternatives. This included emoji intended for information not fun. Color made them distracting when the wanted information was anything else. A monochrome font could not solve this because most emoji are too complex to display clearly at normal text sizes without color. They were cumbersome to grep. (Uncommon Unicode characters would have this problem also.) Many had unclear meanings.

Use emoji in your CLIs if you desire. But make them optional. Opt in ideally.

Unicode can be useful. The emoji subset generally are not.