Making real physical prototypes too much can cause you to try to rely on a prototype to solve your problems rather than your brain. Prototyping takes elapsed time that you are usually not working on the problem any more and money. We work hard at increasing the amount of digital prototyping we do to move quickly, but it does require more thought and consideration as you’re always trying to approximate the real world in the digital one so knowing
Good prototypes give concrete evidence of the risk that they are designed to assess is either still a risk (or a complete failure) or no longer a risk and get transferred into the design.