Most C++ compilers still implement most of the C++ standard. This thing basically implements C, and adds methods to structs.

That's only technically true. The main C++ compilers in common use basically support, aim to support or have collectively agreed not to support parts of the C++ standard.

> have collectively agreed not to support parts of the C++ standard.

Those parts were ripped out of the standard. (The big one is export templates, where the expert compiler implementers when asked for feedback about how to implement it said "don't").

Touché