Why isn't bark used for animal bedding other than wet reptile and frog environments?

For companies that sell bark, I see it sold for reptiles, frogs or landscaping. Those companies are not selling bark as bedding for other animals like mice, gerbils, sheep, horses, cattle. http://www.ors.od.nih.gov/sr/dvr/drs/nutrition/Documents/SpecsDiets/4F.pdf excludes it for lab animal bedding in section 3.6 b)

Is there a reason bark is not good for bedding with the majority of animals?