Cpp2 is part of the trend for would be "C++ Successor languages" from 2022. The std::println function was standardised in C++ 23, and implementations still don't all provide it in full today.

So in effect Cpp2 pre-dates std::println. Herb will have been aware that it exists and is likely for C++ 23, but it doesn't make sense to ship software which requires features you suspect won't be widely available for several years. A "Hello, world" program should not be relying on bleeding edge features.