Like probably everyone over 50 here, I also started out with the sleeping bag stuffed into a stuff sack and lashed to the bottom of my external frame pack. (The pack bag didn't go all the way to the bottom; it was designed for the sleeping bag not to be inside the pack.)

When I got my first internal frame pack, designed to store the sleeping bag inside, I got rid of the stuff sack. This was partly because it made sense, but mostly because Colin Fletcher, in Complete Walker II (or was it III?) told us that internal frame packs were designed to have the sleeping bag tucked solidly into all the small corners of the bottom of the pack, to help the pack "work" properly. After all, if Colin said it, it must be true, right? (And he'd be the first to yell, "No, not necessarily!" )