FHSS was actually used by the original (2 Mbps) 802.11 radio modems in the mid 90s. It wasn't until 802.11b/a came along a few years later that the world moved to DSSS (along with other innovations such as, er, proper intercompatibility between different vendors' kit!).

AIUI, DSSS was necessary to make use of the full channel bandwidth, but FHSS is more resistant to interference so might be good for the warehouse use case mentioned in another top level comment.