The performance cost in isolation is not high, but the benefits of being able or reinterpret cast the buffer you got form the network and access it directly wit

The performance cost in isolation is not high, but the benefits of being able or reinterpret cast the buffer you got form the network and access it directly without any intermediate preprocessing is high. Most programming languages do not allow accessing fields in an endian agnostic way, you need accessors and a lot of custom code, so the code complexity benefits of ignoring the issue are great.