What’s the difference between showing the end product of your work versus showing all of the stages of your design process?

In the first case, you might want to have an impact, to present it and to impress. Maybe you cannot talk it thru, you cannot present it as product so it must be polished and perfect. There should be storytelling elements, showing the strengths of your solution.

The problem with that : you are not able to tell the difficulties, the discoveries, the problems you have faced. So is less personal is more constructed. You can try to control the instantaneous impression, but it’s more difficult to convey your creativity, your thinking process and your design personality.

On the other hand when you show the backstage of how you evolved the solution of how you researched possible ideas and how you faced the problems, the obstacles, and the constraints that you met during the ideation process, it shows more your personality as a designer or as a developer, as somebody who is been thinking about the problem and researching it and finding different ways: branching prototypes, iterating versions.

And this is also a way to show the value of your work. So if you want to give depth to your work and be appreciated for your efforts as a designer, showing the evolution of your designs is the best way of doing that, compared to giving flat screens, beautiful rendered without a background history.