Fundamentally the BEAM is very opinionated with a limited range of possible language designs that would work with it. No mutability, e.g. I love the opinionate

Fundamentally the BEAM is very opinionated with a limited range of possible language designs that would work with it. No mutability, e.g. I love the opinionated, constrained nature of Erlang and the BEAM, vs the kitchen sink approach of Java and the JVM.