From the acceptance letter:
"""
if you are worried that this will make Python ugly and turn it
into some sort of inferior Java, then I share you concerns, but I would
like to remind you of another potential ugliness; operator overloading.
C++, Perl and Haskell have operator overloading and it gets abused
something rotten to produce "concise" (a.k.a. line noise) code.
Python also has operator overloading and it is used sensibly, as it
should be. Why?
It's a cultural issue; readability matters.
Python is your language, please use type-hints responsibly :)
"""
I would add metaclasses, generators, etc. all these are already enough to write horrible things.
It is indeed all about "culture", readability is really the cornerstone of Python culture. Type hints when used responsibly are fantastic tool. You could be surprised but they really improve readability, it's like a succinct docstring. I discovered this while recently reading through one large codebase.
Moreover, typechecker will tell you when your "docs" do not reflect actual semantics.
Finally, I would like to point out that typing.py and Mypy are pure Python, no magic :-) At the same time "import typing" is very in the spirit of "import antigravity".
I hope Python gradual typing could become alternative to Java/C++/etc. BDSM-style typing and one day we could say: "Come join us! Typing is fun again" :-)