In an enterprise-y environment, it's not always possible to keep upgrading to the latest. So assuming someone creates a project based on f-strings, that would be python 3.6+ only. Whereas using string.format will work across entire python 3+. Is that worth the upgrade- I'm not convinced.
Yes, and? This still means that if someone gets the latest Python the f-strings should be used everywhere, because supposedly they solve every and all problems that the previous ones solved and some.
But in reality, you can't ( and shouldn't ) go back and change how the rest of the legacy codebase does things just because there's a new way to do it.
