out of pocket health care expenses for her are approximately $1500-$2000
Essentially you can pay for these expenses with pretax dollars. That is the main reason right there.
Aside from that, HSA can be used as an additional Roth IRA (sort of). It's pretax dollars, tax free earnings, and tax free distribution (for qualified medical expenses) The way I look at it, you can pretty well count on having medical expenses at some point in your life, especially when you get old. After age 65, you can also take the money out without the 20% penalty, but you still have to pay income tax, as you would on a traditional IRA.
I have a feeling these are not going to be around very long, which is sad, because I think it offers lots of value and choice for insurance plans. Go figure though. I would take advantage while you can.