It's true that 480 isn't on the list, but you'll notice there is a big skip in the list between 360 and 720, so if you want something in between, 480 is a good choice since it's still a multiple of 12.
Yeah, to be clear, I think there are many important factors that go into choosing a shard count, and blindly jumping to something just because it's some platonic mathematical ideal seems naive. I just thought this is a neat related fact and is probably a good starting point if you're in the process of choosing a shard count.
