It’s geared toward the “All I need is one bag that can fit in the footwell in front of me” crowd. It’s annoying for the rest of the world, though, because the supersaver fare is what shows up when doing a generic search. Then you find out to get their regular fare, it’s another 50 to 100 bucks.

I think the standard accessories for this are no seat assignment until the day of the flight when you check in, no carry-on baggage, no checked baggage unless you pay a lot extra for it, and you board last.