Usability is not the same as habit-forming
The Hook Model is about building products that are habit forming. That is different from building products which satisfy user needs.
For example, a toilet brush has been designed carefully to satisfy user needs (for cleaning toilets)...

...but this product is not habit forming because users don't need to, or want to use the toilet brush habitually.
On the other hand, a product like the Fitbit does satisfy both user needs and the Hook Model because it provides users with a trigger to check the watch, a sense of reward for interacting with the product ("you've walked 5 miles today!"), and a virtuous cycle of behavior which causes the user to want to keep using/checking the watch:

The conceptual difference between user needs and habit formation is important for designers to understand:
- Not all products can be habit-forming even with the best design.
- Habit-forming products benefit from being designed with the Hook Model or with other behavioral models, because user needs alone usually do not capture the behavioral user experience needed for a product to become habit forming.