The no VM thing I think is a downside. Sure raw performance is nice but not having a process eat all system cou resources is the true beauty of Erlang and Elixir to allow you to self heal. Are you handling that with this library?
At least Rust doesn't have a garbage collector, so when the actor is stopped + dropped, it'll cleanup not only it's state but also it's message queue's flushing them so that all memory is released at the time of drop.