"scp and i'm done" is completely possible with Elixir/Erlang. It is how we deploy lots of erlang pages. Copy beam files, have erlang check periodically if any beam files have changed and reload them.
Sure I suppose that's possible but it just seems a little gross. At least with 'scp binary' your first and all subsequent deploys use the same process so tools like Ansible can help you out. I guess that's what I was referring to -- repeatable deploys; pushing a new a BEAM release package is a more involved process than just with a single binary.
I totally agree, being able to just ship binaries around is fantastic. No complex process necessary, things Just Work™.
However, if you're ok with a little extra process, Elixir allows for hot code reloads. To be fair, most use cases probably don't need it, but it's a pretty great option to have in your tool belt.
Using erlang releases is in no way mandatory.