Given GBI supers tell us they need to rebuild natural sod faced bunkers every few years, I think eco-bunker and whoever copies them probably have a viable solution for that design style. When I priced them a few years ago for a project, it was like $4.50 per LF, and those strips are only 4" high or so. Thus, a one foot tall grass face was over $12 per running foot, and some of those as seen in the photo above would be really expensive. Of course, to me "really expensive" is defined as something above what my then client wanted to pay.
I will guess the price will come down at some point, and it will be like bunker liners, what starts at higher end courses will be common in 5-10 years, and almost standard in 10-15.