Network formats (at least the popular ones) typically transmit in "network byte order", i.e most significant byte first. There are advantages in being able to

Network formats (at least the popular ones) typically transmit in "network byte order", i.e most significant byte first. There are advantages in being able to read a hex dump without manually reversing the bytes in your head for every field that is two bytes or larger. Far from antiquated I would consider the selection of big-endian formats as an indication they actually gave some thought about what they were doing, ranking debugging convenience higher than a marginal efficiency gain on some cpus. The same consideration generally applies to all binary formats intended to be portable across systems.