I have scripts I use locally that are untouched in almost a decade that use
/usr/bin/python.
I'm thinking about scripts that are written and distributed to people running on different, unknown, Linux distros. Obviously if you're only targeting your own machines, there's no problem. But if you want to write a script that will work for arbitrary Linux users, what should you do? I imagine it's not yet a safe assumption that python3 is installed everywhere, but on the other hand, Ubuntu and Fedora are both looking at dropping Python 2, so without some kind of compatibility shim it won't be safe to assume there's a python command.