I don't usually use them but my boat only sits on a pontoon for as long as it takes me to pull the trailer out of the water and get suited up but I would for any length of stay.
Many pontoons have sharp corners on them as do some older boats! It doesn't take much to tear hypalon on a sharp edge and it's surprising how Sods Law means the rubbing strake is at the wrong height for what you are rubbing on...
I've often wondered why they don't offer RIB tubes out of the same stuff they make fenders out of. Well I suppose they do - it's called a Mac