Doesn't affect many people, but pet fees are $50 less as well. That's $150 savings. If I'm flying with my cat, which is usually the case, I don't even bother to look at other airline deals.
It looks like Southwest's mobile boarding pass (which is only available when flying out certain airports) does not use Passbook, and it simply asks you to save a screenshot of the boarding pass to your camera roll.
This is pretty rough. I can't imagine why they are doing this.