That sounds about right; I've seen it listed at 0.45, but that's quibbling. I don't agree that this is extremely small, however. If you were just thinking in terms of r-value per unit ounce, the pad offers more than the neo-air itself does --- stands to reason, ccf is pretty good insulation.

More importantly for me is that I can apply it where I want to. I'm not into (nor capable of) the sort of detailed analysis that folks on BPL get into about this sort of thing, but from trying it both ways it certainly "feels" to me that putting a thin ccf pad on top of an inflatable helps significantly (and more than putting the same ccf pad below the inflatable).

I definitely wouldn't suggest that the neo-air is the be-all and end-all for all hikers, just that for folks already considering one, combining the lighter version with one or more thinlight pads might be a winning combination.
It's worked well for me, in any event, allowing me to use the same inflatable pad in a variety of conditions.