For anyone wondering, this is the really fine bark substrate that looks much like coffee grounds once hydrated.
I really the bark substrates over either soil or gravel. Coconut bark has imo a pleasant, earthy aroma that tends to mask other, less pleasant enclosure smells. It retains moisture and temperature well and seems to be resistant to the growth of fungus. Finally, it has a pleasing, natural appearance.
Right now I'm mixing two of these bricks with one brick of the coarse bark and I get PLENTY of substrate for four enclosures, each enclosure about 3.9 square feet in area and with a substrate depth of about 2.5". I've been changing the substrate every six months, but realistically it could probably last twice as long because none of my enclosures have ever really NEEDED to be changed after half a year.