A very good use for multiple assignment is setting a bunch of variables to the same number.
Below is a demonstration:
>>> vowels = consonants = total = 0
>>> mystr = "abcdefghi"
>>> for char in mystr:
... if char in "aeiou":
... vowels += 1
... elif char in "bcdfghjklmnpqrstvwxyz":
... consonants += 1
... total += 1
...
>>> print "Vowels: {}\nConsonants: {}\nTotal: {}".format(vowels, consonants, total)
Vowels: 3
Consonants: 6
Total: 9
>>>
Without multiple assignment, I'd have to do this:
>>> vowels = 0
>>> consonants = 0
>>> total = 0
As you can see, this is a lot more long-winded.
Summed up, multiple assignment is just Python syntax sugar to make things easier/cleaner.