You can use a BEAM system to orchestrate other code, too. As ports, port drivers, nifs, c-nodes, just other OS processes spawned and using IPC/sockets. Lots of options. Using Erlang to supervise an OS process doing work perhaps enhances the isolation principles of BEAM.

It's snarky but I think it is a fair comparison. You do have extra capabilities over what BEAM offers, in exchange for having to manually handle a lot of things BEAM either handles invisibly or at least comes with usable defaults for.