Is spanish a language worth learning today. If you live you Iceland and are planning spending time in Japan time is probably better spent learning Japanese and Icelandic. But if your going to Spain... you get the picture...
I think you are asking us and yourself the wrong question. You should be asking what is C++ used for and can I see myself doing that or would knowing more about _____ help me with _____.
Until you know what the job is you don’t know what tools you need.