this distinction may seem pedantic, but in practice it's critical; concurrency is necessary but not sufficient for parallelism, and often, more important, too. designing a process of concurrency entails identifying task interdependencies and untangling the unnecessary ones
parallelizing a process typically entails first enabling it to be concurrent by finding all its independent subtasks, and then scheduling those tasks to be run optimally, potentially in parallel if you have the capability
however, even w/o the last step, there are benefits