They’re great for early game— I’ve used them through the experimental feature to hold mob drops and other small-count loot. And I like being able to access them right from the inventory, though it is a bit tricky to get the preferred item out.
That’s all my praise. Shulker boxes hold lots more total and are way better post-dragon. And they could add the inventory access mechanic to shulker boxes.
That’s fair— I’ve had to go looking for rabbits and breed them on each world I’ve gotten bundles in.