I don't know a lot about erlang but i doubt it makes parallelism easy all of the time. I'm sure there are many cases when the default actor model works great,

I don't know a lot about erlang but i doubt it makes parallelism easy all of the time. I'm sure there are many cases when the default actor model works great, but that's not a reasonable model for _every_ problem. Shared memory multithreading (for all of its faults) can be very effective for certain kinds of problems. So it can be worth the difficulty.