I think it has more to do with memory use. See for instance the "65535 interfaces ought to be enough" thread. If you allocate a bazillion of a certain structure

I think it has more to do with memory use. See for instance the "65535 interfaces ought to be enough" thread. If you allocate a bazillion of a certain structure, then using the shortest allocation unit for its fields can make a difference, especially if you have a lot of these "small" fields.