After completing the wizard, the user gets a view with an artificial loading indicator. In cases like this it’s important to increase the perceived value of the product. If the user spends ~5 minutes answering questions, but the results appear instantly, they might feel as if the product is not really doing anything and all his work was for nothing. Showing a nice loading animation for just a few seconds will prevent this.
The designer probably used these colors because they thought it looked cool. Stop it. Make it because it’s right, because it has meaning, because it will help users solve a problem, or because it will help sell your product. Don’t do it just because it looks cool!