When designing a software application it can become extremely complex really quick. If you start your initial designs in a design application like Sketch, Indesign, Figma, it can be very challenging to quick made design changes that’s require a lot rework. Also, because of the computer and software being intermediaries between your ideas and your design, they the slow the idea process down.
Creating paper prototypes and storyboard is best the way to get your ideas out of your head and in a visible format that be observed and tested. Also, when starting with hand drawn paper prototypes it prevents the idea from getting lost in aesthetic details.
I’ve been working on designing a travel app and have been using the paper prototyping method. I absolutely love it and will always use it from now on.