this is definitely Reindeer Lichen colored.
florists use it a lot. it is dead, but when you mist it it softens.
if you want to reuse it it is better to moisten it prior to handling, since it totally crumbles when dry.
it is just there for decoration, but it might be considered to be a mulch of sorts..it covers the soil, so might keep the surface moister and raise humidity a bit around the pot if you keep it moist.
