If you are travelling with family and possibly a nanny or two, they are a usable perk on top of the 1 or 2 guests status grants you. I've often seen those types of groups sat split between J and Y on board too so the passes could give everyone some form of lounge access without clogging up AM.

That said, I've never used one and they are of very limited benefit for single travellers.

But I quite like the way QR protect the premium product, and certainly the platinum lounges are very good compared with many other airline's J lounge offerings