There is a difference between a landspout and supercell tornado, right? It's almost the same type of distinction in the two photos above.
In alot of the Florida and east coast waterspout pics and video I've seen, the are slender, fairly weak and protruding from a rather flat and smooth cloud base and even elevated abit by comparison. They often form under towering cumulus, showers, and weak/moderate thunderstorms similar to landspouts. The dynamics are different than that of supercell/meso spawned tornadoes.
These two photos are pretty clear to me that they are supercells and the Sydney event was absolutely a supercell without a doubt...complete with golfball hail and other winds that assaulted them. They definitely look like strong tornadoes to me....but over water.
Now, I know that this all is going to lead into a battle of symantics and definitions both old and new. I think that the parent storm structure for the "waterspout" needs to be clearly distinguished as these two photos do. In that regard, we should distinguish the type of "waterspout" it is. Perhaps we need to create a new definition for water-born supercell tornadoes and call them "waternados" or "wetnados" or "aquanados" or "H2Onados" or "Seanados"....LOL