In the UK wood pellets are used for both stoves and horse bedding. No mention was ever made by the supplier of the composition of the wood powder from which they were compressed. Sales tax at 20% is levied on pellets used for bedding, when used for fuel there is no tax levied. The bags are the same.
The pellets absorb water readily and in doing so they expand and break down into powder. The powder is heavy enough to lie on the ground
It is better to lay down rubber matter to make cleaning easier.
After using the material I would say that it makes mucking out easier.
But there are two things to watch out for - the dust can in dry weather irritate the horse's throat unless the powder is kept moist.
The hooves of the horse will dry out in hot summer weather.
A big advantage to the barn owner is that the muck heaps are significantly smaller.
Compared with the use of straw, wood powder is 21st century technology. Straw was traditionally used because it was in years gone by freely available on the farm.
But straw has little moisture absorption capability and is bulky.
Note that wood chips do not have the absorption capability of wood powder pellets
I'd use wood powder again but I'd regularly sprinkle the bed with a watering can.
I might try blending powder with wood chips.
Note in the UK, muck heaps are coming into increasing inspection by the environmental agencies. The use of wood powder reduces the size of the problem.