AT&T Offers a SIM-only Plan --- Tell Me Why This is Good, Again?

AT&T is offering a new way to get service: SIM-only. My question is: why is this supposed to be good?

Go to the online store, and for $10.00 minus a $5.00 "online discount" you can snag a SIM. This option obviously is for those who have an unlocked or AT&T-locked cell phone.

But the service still has a 2-year contract. The 2-year contract has always been justified as a way to subsidize the handset. In this case, what handset?

So, my question is, what's so good about it? I could get a free handset with a 2-year contract, and dump the cell phone, either donating it or selling it. Where's the appeal? This costs me $5.

Right now there are around 14 free phones at the AT&T online store (there are so many I may have counted incorrectly). While it would be great if we could get a SIM like this - and all phones were unlocked - that's not what this is.

On the other hand, if it's a start in that direction, that would be great. In the U.S., I seriously doubt it, though.