It's fine to have a goal for general purpose compatibility with C++, though that's harder than it sounds. More than likely there will have to be lines drawn in the sand like "no ABI compatibility ever" or "assumes you're using only clang toolchains" which will necessarily limit how generally adoptable the language is.
It's clear that compatibility is a goal but it's clearly not a feature yet, so we should be careful to talk about carbon as if it has that feature, especially given how hard that feature will be to implement and support.
I'm more confident that Google will be able to meaningfully use carbon in its monorepo than I am that it will be a good replacement for C and C++ for any given non-Google project.
It's clear that compatibility is a goal but it's clearly not a feature yet, so we should be careful to talk about carbon as if it has that feature, especially given how hard that feature will be to implement and support.
I'm more confident that Google will be able to meaningfully use carbon in its monorepo than I am that it will be a good replacement for C and C++ for any given non-Google project.