One of the issues with Python 3 is that there isn’t really one killer feature, it’s countless little ones. Many believe 3.6 was the first release where they added up to enough of a benefit (though f-strings are a big help for many projects).

Regardless it no longer matters, the Python 2 ecosystem is now rotting as packages drop support. Every week I have to make one or two hot fixes somewhere to forcibly pin to an old version to fix something.