Perhaps you might not have been looking close enough. If you are not blasting through flour very quickly and you leave it in a bag, even clipped, you can get weevils and mites. This is not new. Ask elderly home cooks that you know. Putting it in sealed containers or jars, however, it can keep for a good while.

Extra protein?

Yes or more correctly, my wife and I used to until we started putting all such goods (flour, oats, rice) in sealed glass containers.

Yes, not terribly often but enough that the simple act of putting it in an airtight container is worth it.