They're solid vehicles in terms of higher rates of inflation. However, it looks like, at least over the short-term, we're beyond that.
They're ultra low fee (0.04%) and provide solid protection against inflation.
If you're asking this because you believe inflation will creep up again, I do see value in them. However, if it stays relatively low, they don't provide much advantage. This is likely why the fund has had more than $3.8B~ in outflows over the last few years.
I'm curious, any particular reason you're interested in them now?