In my experience, I tend to only use memoryview() for “bytes-like” buffers (but see Issue 23756 about clarifying what this means). Example from /Lib/_compression.py:67:

def readinto(self, b):
    with memoryview(b) as view, view.cast("B") as byte_view:
        data = self.read(len(byte_view))
        byte_view[:len(data)] = data
    return len(data)

Fixing cast("B") or adding a memoryview(raw=True) mode could probably help when all you want is a byte buffer.