I'm a little surprised at where Erlang features in the list. I've never used it personally, but have heard so much about it being an amazing, performant language. I wonder why it's so time/energy/memory inefficient for the algorithms used in this exercise.
BEAM has a 'busy wait' feature. Schedulers with no jobs to do will remain active so they can respond to new jobs faster. You can turn this down so that the schedulers go to sleep quicker, reducing CPU usage.
+sbwt none|very_short|short|medium|long|very_long
Sets scheduler busy wait threshold. Defaults to medium. The threshold
determines how long schedulers are to busy wait when running out of work
before going to sleep.
I’d certainly put Erlang (and Elixir) in the class of scripting languages. In that category it beats out most of the other classic scripting languages like Python, Ruby, Perl, and Lua at execution speed and energy usage, aside from JavaScript and oddly PHP.
For being a mostly pure functional language it performs pretty well in that category. To the parent comment’s question, the reputation for solid performance likely comes from Ruby/Python developers. When dealing with web server applications it really shines due to how it handles concurrency. Also NIFs are really easy to write, especially in Rust.
It's built for massively distributed systems and is efficient at that I believe. It's not really designed to be a replacement for numeric languages like C/C++/Fortran/Ada...etc. It's a high level language, so what you gain in user development efficiency, you lose in performance. Someone knowledgeable in Erlang could confirm though as I'm being general.
