Well, the thing about the quick-releases is that they must be tightened securely, and they must be well-made and still in good condition. If the serrations are worn off, if it's not a good QR, etc, it's likely that it won't work as well. The thing that really is nice about the nuts is that you know you can rely on them. A handy feature! Certainly in recent years, with the move to vertical dropouts, inferior quick-releases have become common, especially the open-cam type from my second link above. Blech. Those are no good, stay away from them for any purpose! In any case, given that the nuts take maybe a few seconds longer to remove or reinstall, I don't see any reason not to use them, in any case. There's nothing wrong with them, it's just that a QR really can and does work, in spite of common belief to the contrary.