I think if you are starting from nothing, message passing is actually a more intuitive way to think about and design large distributed programs, because you don't need to deal with a lot of the complexities of OO languages such as state and handling distributed communication / disaster recovery.

Running processes in parallel is cheap in Erlang, so you can run hundreds of thousands of them in parallel on a commodity servers. Generally, if you are running any sort of high-traffic service with a lot of dynamic stuff happening, there are probably parts of it that Erlang/OTP can help make more efficient and easier to maintain.