Smartpens have been around for a longtime but the process can be difficult for some . Also the books are a ongoing costs and you cannot rub out the ink and start again.
The rocketbook does allow you to rub out your work and start again but it’s selling point is the ability to transfer work through a scan and it does accurately represent your drawing as the image below exemplifies
In the example I have stated what I think it would be good for. But it’s by no means exhaustive .