Heart of the Sea renewability

As it stands, there are a limited amount of hearts in a world that can be used to make the conduit. Beacons can already be made as many times as your willing to fight a wither. My idea is to make the heart of the sea a very rare treasure for fishing, rarer than nautilus shells. Or perhaps available as a master trade from a villager. This will allow people, especially in heavy multiplayer worlds where a majority of buried treasure has already been looted, to make conduits for awesome underwater bases or a convenience while standing in rain.