I'm not familiar with that product at all, but I can get a big bag of fine grade orchid moss at Lowes for around 1/3 of what you will probably pay for that product. It will retain the moisture just as well if not better.
My tort will graze on moss the same as grass, luckily the moss that grows rampant here is short and soft and I have had no issues with impaction.
Sphagnum moss can get quit "tuff" and I wouldn't risk it. I'm not familiar with the other kinds but to be on the safe side, I wouldn't use any moss in an area that your tort may reach.
*Note* moss grows crazy where I live and is literally living underneath the grass in my yard. I don't purposefully offer it but have no way of getting rid of it.