I would think that's not the best way. Looks unnatural to me, and you probably won't have the quality of live rock filtration going on in that type of material. It's just an option.
The best choice for anyone would be to place the frags on rocks using the super glue gel. Or place the frag plugs in holes and let the zoas grow.
If you want to remove them from plugs, then you can glue to the rocks.
Not to fire that product, just my personal opinion.
Grandis.