I write a good deal of python and I can't think of a line of code that I would use it for besides the while loop on a non-iterable data source, which is such a once in a blue moon case. As mentioned by others, the operator invites more ways to do the same thing, which is not what Python has been viewed as being about.
Victor Stinner made a demonstration pull request using the walrus operator in the standard library where it makes sense. On balance it removes several hundred lines and often makes the code much clearer, e.g. https://github.com/python/cpython/pull/8122/files#diff-78e8e...
