Water in cauldron is not water

The reasons:
1. Water in cauldron isn't transparent, while water itself is.
2. Water in cauldron don't make any damage to mobs that take damage from water(Enderman, blaze, strider)  while water itself does.
3. Water in cauldron cannot be used for trident with enchantment "riptide", while water itself can.
4. In Water in cauldron you can breathe endlessly, while in water itself you can't
5. You don't make bubbles when you fall into the cauldron, while falling in water itself makes.