Exactly. The point is that the abstracted Point hides implementation details like the underlying representation, which is good as far as it goes because it prevents goofs like overflow and trucation due to incorrect type conversions, etc...

But the second you need to match that abstraction to the code from some other developer which doesn't use it, you need that underlying representation back again. And this kind of mismatch isn't an uncommon edge case, it's the pervasive truth of modern development.

Basically: C++ can't win here, and it would be better not to try IMHO.