The fact that tempfile.TemporaryFile() has a "name" integer attribute  causes weird behavior when interacting with libraries that rely on this attribute being a valid string for file objects.
For instance, it led to this exception with the "tarfile" module, which I resolved by using a NamedTemporaryFile():

>>> tarfile.open(fileobj=tempfile.TemporaryFile(), mode='w')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.4/tarfile.py", line 1585, in open
    return cls.taropen(name, mode, fileobj, **kwargs)
  File "/usr/lib/python3.4/tarfile.py", line 1595, in taropen
    return cls(name, mode, fileobj, **kwargs)
  File "/usr/lib/python3.4/tarfile.py", line 1431, in __init__
    self.name = os.path.abspath(name) if name else None
  File "/usr/lib/python3.4/posixpath.py", line 360, in abspath
    if not isabs(path):
  File "/usr/lib/python3.4/posixpath.py", line 64, in isabs
    return s.startswith(sep)
AttributeError: 'int' object has no attribute 'startswith'

Which is caused by these lines in the "tarfile" module:

if name is None and hasattr(fileobj, "name"):
    name = fileobj.name

If TemporaryFile() didn't have a name attribute, tarfile, which doesn't really need the file name, would simply have continued without errors.

I am not aware of any place where this "name" integer attribute is actually useful, and, as a matter of fact, it is not even documented: http://docs.python.org/3.4/library/tempfile.html#tempfile.TemporaryFile