The wikipedia examples are somewhat misleading.

The string "My name is {name} and I am {age} years old" is a plain string. By itself, there is no interpolation:

    >>> x = "My name is {name} and I am {age} years old"
    >>> x
    'My name is {name} and I am {age} years old'

The format function is what confers meaning. This is identical to a standard printf situation, wherein the string "%d %x" encodes a transformation but in and of itself isn't a transformation.

Contrast with the proposal for f-strings:

    >>> x = f"My name is {name} and I am {age} years old"
    # this is an error unless name and age are defined

The literal mandates a particular interpretation, and the f-string cannot exist outside of that in the same way that the standard string does. Or as the PEP puts it:

> It should be noted that an f-string is really an expression evaluated at run time, not a constant value.