The raft is mostly garbage but certainly has a few uses including a floating construction platform, or if you put a few in a row as a floating bridge of sorts. I'd agree it's mostly useful for very short distance and coastal exploration. Darn thing is so. Slow.

My main use for it is when I mess up and have to go get my karve or longboat back, and not much else since it's slow, has no storage, and gets broken easily.