or maybe erlang / elixir do not have 1/1000th of the libraries and features available to C++ thus it's more efficient to port what can be ported? would you rather have the whole of C++ ported to erlang?

Honestly, erlang was designed for telephone use cases and for high concurrency, erlang as an idea is fundamentally really awesome.

And elixir on top of erlang really makes the syntax easier to use. Gleam is interesting too!

Depending upon the amount of concurrency needed, erlang can be absolutely good for the situation.

The only gripe that I might have seen online with Elixir might be that it is functional language (and I think has its own way of doing things) and a lot of the times people start with other languages which can scale to only a certain point.

Either way, Erlang VM/OTP model does feel really cool to me. Fun fact: but Erlang was a virtual machine before it was cool (Java)

I definitely wish to learn elixir someday (don't quote me on that though :-D), just because of how unique Erlang/Elixir are compared to many languages in such sense of scalability.

Although not a 1:1 Apples but I also wish to know more when golang is more fit as compared to elixir as currently, I usually prefer golang as a swiss knife with its decent stdlib,cross-compilation,portability features.