Think you may be right. The one concern I have is that deflation has an expiration date, and it seems unlikely that it will last thirty years. I would view this vehicle as a trade rather than a core investment, since it's so levered to implied forward rates.
This is a zero coupon bond etf, with a 25 year maturity. I bought it because I see interest rates still moving down, a deflationary scenario. It also helps lower the risk profile of my portfolio. I don't see unemployment coming down for several years. The federal reserve won't be raising interest rates any time soon. I think I'll still own this a year from now, but if the economy gets off life support, it will be time to sell this.