It comes at a cost, of course. You don't really have shared memory state, which is often easiest to conceptually think about. So you are just transforming the

It comes at a cost, of course. You don't really have shared memory state, which is often easiest to conceptually think about. So you are just transforming the problem into a data sharing problem between interpreters, which requires careful thought on both the language side for abstractions, and the consumer side to use right. It also makes the tooling and verification much harder in practice - for example, you aren't reasoning about deadlocks in a single process anymore, but both within a single process and across any processes it communicates with. At an abstract level, they are transformable into each other. At a pragmatic level, well, there is a good reason you mostly see tooling for single-process multi-threaded programs :)