It's still got the same limiting reagent which is the spell slot. Whether it uses a full action or not is irrelevant because while it is a bonus action, it's restricted to a form that takes more damage in by default, making the healing efficiency a lot worse. It's a LOT less bang for your precious limited spell slots, especially as a Moon Druid where you have less spell slots than Land druid to begin with.
Well you can say it doesn't work for you but it's a spell for a certain situation. Perhaps you only have a bonus action left and you need to heal? Perhaps you don't want to change back? It may not be ideal but it provides a chance to heal, which may not be ideal but healing nonetheless.
Healing Word and Cure Wounds are also dependent upon the current situation.