It's all relative. Plenty people come from Node, Ruby, and Python.
Coming from the Go! world, I view Elixir is trade of speed for OTP out the box niceness. But comparing Elixir to Node, then you're just gaining speed and stability.
And it keeps going -- I very frequently see Go criticized for slowness by C, C++, and Rust developers. It is all about the usecase, which is why I find this topic so interesting. It's one of the few situations Elixir mid-level speed is actually a real world problem.
I get your point. Even without message passing, just in process calculation in Erlang/Elixir is also pretty slow compared to Java.
But in the domain of Web programming, scheduling efficiency is much more important than the speed of execution. If it is a huge batch operation on a single machine, Erlang/Elixir would be terrible.
Similarly, for React there's fiber mechanism -- it's worse according to benchmark, while the user would get a better experience due to a better schedule.
Yeah for numerical stuff but for network stuff which Erlang and its VM was created for it's great for web application. Having the option to write Rust, C, etc.. with NIF is a good compromise.