I do know my tools, actually (having helped create them) - before creating the structs, I did consider this approach, and consciously decided against it for roughly the reasons described.

I'm talking about a distinct problem from programmers not knowing their tools - programmers who do know and understand their tools quite well, but decide, for whatever horrible reason, that those tools are "quite good enough", and insist on going from scratch. Sometimes justified, and usually not - and it can lead to a great deal of harm in the way of unmaintainable bloat.