[purple_ducks]

> which makes data parallelism awesome and easy

There's still going to be a finite number of cores on a machine. I can't see gaining parallelism being that big a boost (as opposed to gaining concurrency(if not already there))

[steveklabnik]

I would expect this task to be CPU bound, not IO bound. Maybe that’s incorrect.

[zozbot123]

You'd be surprised, even consumer-grade CPUs are fast approaching manycore territory these days. Just look e.g. at AMD's Threadripper, which BTW is being targeted at hobbyists and enthusiasts, not just professionals. (There are also ARM-based 'desktops'/'workstations' with comparable number of cores.) If we want to make anywhere near full use of these capabilities, we'll need easy parallelization (for applicable problems) to become essentially ubiquitous. Rust and Rayon are perfect for that.