This is the type erasure approach, whose cons are mentioned in the article.

It's the C approach, strong typing doesn't mix well with raw memory access.

The very article we are discussing shows you a way how to do that type safely in C. It uses #include which is a very idiomatic way to do this in C, and an example where a preprocessor-based approach is more flexible, than e.g. a module system.

Nim is strongly typed and allows raw memory access just fine.