From product C code perspective, this code is of course bad. But here idea was to show data manipulation closer to how it is shown in documentation.
Also a lot requests have dynamic size and cannot be as easily packed and serialized to be sent over the "wire". So for example you could put pointer to string into struct, malloc required space, then assign pointer. After when you want to send data you would have to write serialization methods to put it in correct order. It is all fine and should be done when you build bulletproof system to manage X11. But here these techniques just draws too much attention away from X11.
Also a lot requests have dynamic size and cannot be as easily packed and serialized to be sent over the "wire". So for example you could put pointer to string into struct, malloc required space, then assign pointer. After when you want to send data you would have to write serialization methods to put it in correct order. It is all fine and should be done when you build bulletproof system to manage X11. But here these techniques just draws too much attention away from X11.