How?
:shrug: Because you can now interact with the crypts? How is that any more unrealistic than anything inside of the mansion? And how does it take away from the theming when it expounds upon the story of the mansion and its inhabitants and includes a supernatural element which is interactive?
So, you ask why is this great? Well, it adds to the backstory of the mansion by focusing on the characters within, it is interactive, and provides a way to break up the time waiting to ride, or is starring at brick and canvas more entertaining to you?