CracktowerIsn't that similar to "lose your tinder kit and you lose your fire source?" You could lose your pack as well. One person's gimmick is another's innovative idea. YMMV
CracktowerIt is an extra to carry nothing wrong with a backup. I lost my glasses on a trip last year second day in and had to hike the next 5 days without glasses. That sucked not having a backup. It isn't like I am taking a huge weight penalty to have a second spark source.