Explain the importance of having a test coupled with real users’ views of the product at the end of the development effort, even if it is the test of a prototype and not the fully developed software?

There are a number of reasons why a test of a product with real users' views are important, even if the software at hand is in an unfinished condition.  I'll outline these reasons in more detail below.

1. Software testing is an important stage of development as it provides shareholders and investors with an opportunity to envisage how a product will perform.  If the test is deemed a failure, investors then have an opportunity to correct issues before full release of the software.
2. User testing is another significant part of the software development process.  You may have heard of alpha testing, and the wider known beta testing of computer software, such as games.  These pre-complete releases allow real users to test the software and report any bugs or issues that need to be corrected prior to official release. 
   
3. Another key pre-release software test is that of destructive testing.  Basically, users are asked to try to make the software "break" or "fail" by experimenting with different inputs.  It's important that these defects are reported and fixed prior to release to avoid huge complications in the future. 
   

There are a huge number of different tests that are executed on software prior to its full release.  The benefit of these tests, couples with real users' views, is that developers and shareholders alike can fix any issues and be sure that their product is at the highest standard before release. 

Here's a short video that talks in a little more detail about beta testing: