Hadn't thought of that. Interesting experiment.

Welding torch strikers (like the one you linked) basically capture some gas/air mix in the cup and then ignite it. That doesn't take a very hot spark. Still, the flint and the spring tension can be crudely adjusted for a spark that's more impressive than an empty Bic.

The main problem IMO is that, unlike a handheld flint and steel, the torch striker doesn't deliver the spark exactly where you want it. An option might be using the cup as your ultra-fine tinder holder, underneath a bundle that will take a flame that lasts only a second or so.

The only natural materials that I can reliably light with an old-school flint striker (i.e., not a ferro rod) are fluffed-up airborne seeds like cattail down, thistle down, and dandelion fuzz. Cattail heads are the best, and up here our winters are pretty dry so they work fairly consistently.