A quick search yields an R value of 9.6-20 per inch for already available aerogel insulating materials. So a standard exterior wall would have a 3.5"(2x4) or 5.5" (2x6) cavity giving R values of 33.6 and 52.8 respectively at the lower efficiency and cheaper options. That is better performance than pretty much any other option, but the cost is like 10-30 times that of other options.
If they are containing the aerogel granules in glass, which seems to be the case, the thermal bridging would be an issue for efficiency. A solid glass block has an R value of 1.15... A triple glazed window has an R value of 7-8.
The better option than glass block would be filling the cavity of a double glazed window with aerogel granules, which would cut down on thermal bridging to the just the sash/casing and would be more economically viable for production.