The times I've used array, it was a common data structure for communicating with a C extension. You could use a Python list, but that's not just slower but more

The times I've used array, it was a common data structure for communicating with a C extension. You could use a Python list, but that's not just slower but more of a pain to deal with on the C side. (This was before numpy was everywhere; I don't know how much fun that might be to work with from C.) If you're going pure Python then space is a better reason than speed. I'm not sure an array is even as fast as a list.