That‘s not correct as stated.
Elixir is commonly installed precompiled. By default those precompiled elixir versions are compiled using the oldest supported otp version. With beam files being forward compatible you can use those compiled beam files with all officially supported otp versions.
This means elixir can only depend on otp features of that oldest otp version though. Sometimes elixir does enable integration with such new features behind compile time flags though, so that given a new enough otp version at compile time those integrations will become available. That‘s what those -otp-xx tags state - getting a precompiled elixir installation compiled with the OTP version of the tag potentially enabling integration with features of that or older otp versions.
In that process no files of elixir would be compiled locally - though compiling from source is always possible.
Now being able to install elixir doesn‘t meant it can run by itself. That‘s where a locally installed erlang starts to be required.
