I'm not sure this method is actually "standard". For many use cases there is an obvious "null" value of the desired type (for example, just set an int variable to 0), so there's no need to use None.

For use cases where you can't just initialize the variable to the "null" value of its type (because that value has some other meaning for your program), then the true type of the variable isn't just the type you're thinking (e.g., not just an int), because you need to be able to distinguish the variable having the "null" value from it not being set at all (the None case). And for that kind of use case, Python's type hints are correctly forcing you to declare that variable's type the way that reflects the actual situation.

* Python should have a way of declaring variables without setting them to None, so we can type hint them to their actual types. Pre-declaration is very important for a prototyping language, and needs to be done in a way that the variable is visible to dir().

* Come up with a cleaner syntax than the wordy Optional[]. Thankfully, they have recently moved on from the ugly Union[a,b] to the more readable a | b. Something more readable could be done for Optional.

    a: int

    b: str | None = None

    if foo:
        x = a
    else:
        x = b

* code readability; all relevant variables are in one place

* Python is a prototyping language, and a very common usage pattern is doing dir(object) to determine the names of all variables that could be set to something.

    class Foo:
        my_int: int

  x: list[str]

  if foo:
    x = []

  x: list[str] | None = None