Why shouldn't you? One of the best parts of software development is the diversity of ideas. Learning a new way of doing things adds to your potential techniques.
My main job is in a garbage collected language but I'm learning rust and know swift.
C++ doesn't enforce you to use them, while the other languages have their memory models enforced by the compiler, hence why I left C++ out.
In large teams no one can prevent the cowboy coder on the team to go C style on a large C++ codebase, specially when code reviews and static analysis are not used.
My main job is in a garbage collected language but I'm learning rust and know swift.