I think it would work as a mulch, and look interesting and good. However I don't think it breaks down fast to add organic matter to the soil, if that is one of your goals for mulch. If not, go for it.

I went to Savannah and got some spanish moss. CHIGGERS. they wont get in the moss (which really isnt a moss) if its up in the tree for some reason im not sure. the best way to keep them out of it on the ground is to dehydrate it... like lay it inside in a sunny window and dont water it or anything or pop it in a food dehydrator. but yes i have read that it makes a great fertilizer go for it. i dont know how fast it grows but it would make sense to throw a small clump in a oak tree or something then youll have a a good supply for later. it wont kill the tree because it doesnt really kill the tree but if it gets to windy it will catch wind and cause the branches to fall im not sure if it will grow on the ground but I know it likes it in trees

Trust me....chiggers thrive in Spanish moss whether it's on the ground OR hanging on tree branches! So do ticks, spiders, mites, and other little pesky critters.

Anyway, you can use it as mulch, but it doesn't stay attractive (alive) long if deprived of sunlight and air circulation aplenty. Give it a try and see what you think.