I am a big believer that you should continually invest in learning and mastering new languages. Each language gives you a different perspective on how to solve problems.

But as far as the right tool to build professional software, there are caveats. Safety, correctness, speed, and maintainability are all important factors in choosing the right tools.

Edit: I should also say I've had plenty of interviewees who couldn't explain the difference between concurrency vs parallelism, and whose knowledge of these concepts was limited to spawning a pthread and locking shared data. Needless to say these people tend to do really poorly at explaining how to scale a distributed system.

Contrast that with the Erlang developers we interviewed, who think in terms of scale. Their answer is almost always something that could accept 10 requests/s or 10 million. Same thing with our Haskell interviewees. They'll answer our algorithms questions by writing out the types and deriving an answers with a single expression. I had an interviewer who was extremely confused by this. We hired the guy that confused him, not only does he understand concurrency, he also understands lazyness and we love lazy developers :)

Is there a good answer when it seems people don't even agree on what those term mean and apply to in CS.

Parallel computing is a type of computation in which many calculations or the execution of processes are carried out simultaneously.

https://akka.io/docs/

Yes, yes it can.