The BEAM runtime is the real win. Your options are Erlang, Elixir and Gleam to get the BEAM.
Out of the 3, I prefer Elixir and Jose is a brilliant leader for it.
The combination of lightweight processes with their own HEAP and the preemptive scheduler means that millions of processes can run on the same machine with consistent execution time, no GC pause, and no worry that a single resource heavy process is going to slow down everything else.
The balance tradeoffs allows you to do a lot of things that would otherwise be poor architectural choices.
LiveView is just one example, where you’re able to completely forgo the need for a frontend framework but get all of the same benefits with lightning fast execution times.
There’s a lot of wins that come from it.
From a AI standpoint, functional code is simpler to trace and maintain because the AI doesn’t have to worry about side effects.
The HA perks are a bonus.