We've had some of our designers at work use this approach. I think it's quite good for illustrating intentions. But then building on top of the designed Storyboard doesn't quite work out.
Storyboards work well for simple apps with standard UI. Once you start building something custom or complex they are a poor tool. If you have a designer then they're likely going to be making custom UI which will need code (maybe lots of it). The Storyboard quickly becomes a crazy mess of placeholder views, implementation details, arrows and blank screens. The designer can no longer use it to demonstrate their ideas and you've probably completely ripped out their original work.
If your only intention is to make a interactive demonstration of screen progressions - then this is perfect. But don't think that this has the same reusability as making a HTML+CSS+JS mockup.
Storyboards work well for simple apps with standard UI. Once you start building something custom or complex they are a poor tool. If you have a designer then they're likely going to be making custom UI which will need code (maybe lots of it). The Storyboard quickly becomes a crazy mess of placeholder views, implementation details, arrows and blank screens. The designer can no longer use it to demonstrate their ideas and you've probably completely ripped out their original work.
If your only intention is to make a interactive demonstration of screen progressions - then this is perfect. But don't think that this has the same reusability as making a HTML+CSS+JS mockup.