@ teletech,
Just a point to consider, I first came across these cases (maybe a dozen) at a GSSF (Glock) match, which is a "lost brass" match. About the only time that I shoot a 9mm is at either a GSSF match (lost brass) or at the Adaptive Defensive Shooting Summit (lost brass). By Sig Academy policies, ammo at the ADSS has to be factory loaded. In a typical GSSF match, I will shoot between 200-300 9mm rounds, and considering this is a lost brass match, that gets to be a bit expensive if I were using specialty brass. Considering that I travel a circuit to both shoot and work these matches, I could easily burn through 10-11 matches worth of ammo. This could amount to 3300 rounds of EXPENSIVE specialty brass fired only once then lost!
For me, especially shooting competitions, it wouldn't be worth it. For the casual recreational shooter (especially a revolver shooter), this could be a reasonable alternative. While I will reload range pick up brass for lost brass matches, I really wouldn't waste my money on this type of brass for my shooting style. Another point to consider is that do we all really find all of the brass that we fire, or do we make sacrifices to the brass gods?
Even though I may find enough of this specialty brass at my matches, I seriously doubt that I would run out and drop $100+ for the dies in order to reload this brass. A side note: while I shot close to 7 matches this year, I worked only 5 matches, and I only saw this brass at 1 match (Summit Point, WV).