I have a hard time finding value in this. Mastering a language take years, so the tool better has some killer feature to make it worth the investment. I can se

I have a hard time finding value in this. Mastering a language take years, so the tool better has some killer feature to make it worth the investment. I can see why Go, if you want an easy to compiled yet middle level language with good concurrency. I can see why erlang, if you want crazy concurrency, and reliability. I can see why rust, if you want c/c++ power, with a modern touch and a safety net. But what is the selling point in D ? Why should I choose D over those for a particular task, and take the time and energy on this on not something else ?