Yep. Fortunately, you can also build a RumpRun Kernel using Erlang as of a few months ago. I haven't tried it yet, but it sounds like it could provide true bare metal.
Even with RumpRun on true bare metal, should that be called "Bare Metal Erlang"? It's not like the erlang code manages the raw memory, contains a driver for the hard disk controller etc.
Clearly there are fewer layers between the erlang code and the bare metal compared to a traditional OS, but still plenty and they do quite a lot of work.