I’m on your side but what you refer to is not static typing and it’s not mandatory either.
Re:New Grad vs. Senior Dev
by eyelidlessness on Sunday March 29, 2020 @10:36AM
(#22719311)
You can get a lot of the benefits of static typing with mypy. I know it's not mandatory, my first sentence acknowledged that.
Only if you just fix whatever breaks in the upgrade and never use the features in Python 3. The static typing benefits alone should either make your software more reliable (benefit to users) or speed up feature delivery (benefit to users).