Pragmatism. It is easier to find JVM-knowledgeable people than to find BEAM-knowledgeable people.
The actor model isn't the only aspect that gives Erlang its robustness. In fact, far more important is its supervisory model, which goes as deep as you want it and can supervise across system boundaries.
I keep waiting for the language that learns these lessons from Erlang with a happier syntax, but I have yet to find it.
Akka does have supervisors. If you find Scala to be a happier syntax than Erlang (eye of the beholder), than Akka is worth looking into. It appears to be directly inspired by OTP and Erlang's "let it crash" ideology.