Yes, and flour comes in a paper bag. It doesn't stop manufacturers from trying to protect their product from incidental moisture contact.
A company who already packs their product in plastic is going to have a much easier time switching to something like this than changing their whole packing line out for box packing machines.
This whole thread had me wondering how much I'm costing them so I could at least pay my share. A quick search got me this page to donate. There's some information about how they are using that money, but it doesn't seem like they've spent much, and it makes me feel like they've got funding from somewhere else that covers their hosting costs.