There's no doubt that the Swiss Champ's magnifying lens is weaker than the Fresnel Magnifying Lenses that are typically used to start survival fires, but don't count it out as an effective survival tool. If used with the right tinder, it can be quite effective.
To get the Swiss Champ's magnifier to work, you must find natural tinders that are easy to ignite. One of the best and most widely available tinders is punkwood, a light spongy, dry-rotted wood found nearly anywhere there are dead trees. Punkwood will easily ignite from the spark of a firesteel or from a Fresnel Magnifying Lens. It can also be charred and turned into a superior form of char-tinder.
To prove my theory on the usefulness of the Swiss Champ's magnifying lens, I took a walk in the Colorado Rockies recently with one goal -- to find a natural tinder that any hiker could find and ignite it with a Swiss Champ magnifying lens. As I was walking, I found an old, dead Pinyon Pine that had been blown down:
(click to enlarge)
I was able to easily dislodge a piece of rotted punkwood with my fingers:
Ignition! The Swiss Champ's magnifying lens easily ignited the punkwood, which burned intensely for over an hour.