I don't know if this is the case everywhere they exist, but collecting moss used to be a profession in Louisiana. Collect the moss, clean it, dry it so it could be sold. Similar to cotton gins, there were moss gins. The last one closed in the 1970s.

Moss was used in mattresses, pillows, insulation in the walls - the end result was called bousillage and the moss was mixed with cattle dung(sometimes), mud, sand, straw, animal hair, etc to stuff in between wooden posts in the early creole cottages.

Because moss was so important from a cultural standpoint, humans would intentionally spread it to areas that it otherwise might not exist. Even with those efforts, Louisiana has seen a decline in spanish moss growth and there have been attempts at conservation efforts to bring it back to the levels it was before. Partially due to invasive ball moss being introduced in the 50s, partially due to air pollution from chemical plants and I'm sure partially due to deforestation and over-collection of the moss in the early 20th century.