There is yet another disadvantage of prototyping: stakeholders (some developers included!) may incline or be willing to believe that the system/product/service is near to completion while it’s still just a prototype.
This is a real risk, the more probable as the more resource constrained is the project.
And it is not a simple matter of awareness, I remember a customer, among many ones, that requested explicitly a throwaway prototype, HTML&JS with no backend connection, just to taste a new feature, than rejected the feature as it was of dubious value. She eventually changed her mind when the project was near release, and asked to put the feature back in. She was in all honesty convinced that she had tested production code and completely forgot it was, on her explicit request, just a prototype.