In the era that these formats were started it was fairly commmon to treat your file format as a dump of memory. It wasn't about preventing competitors from read

In the era that these formats were started it was fairly commmon to treat your file format as a dump of memory. It wasn't about preventing competitors from reading it. It was more about the speed of loading it and the lower overhead. This was before the landscaped had changed so much that the security implications of a format you didn't parse before loading it and the hardware landscape had changed so much that there was no longer a detectable performance hit on parsing a format before loading it. You had interchange formats which were designed to be used between systems and had a defined parseable formats but if your format was meant to be used by you system alone and not shared then it was believed that a memory dump was strictly faster and better for the the user experience. We've since learned a whole about why that is not a good idea but it wasn't always obvious in the before times.