How does mac change the launchpad background effect?

How does mac change the launchpad background effect? I believe most of the Mac users launchpad this function will be put down, but long-term look at the launchpad background will inevitably aesthetic fatigue, now there are ways to replace the dull background effect. At the launchpad interface, you can switch to different effects by pressing COMMAND+OPTION+CONTROL+B. A total of 5 effects are available for you to choose from:

Blur background

Blur Black and white background

Semi-blurred background

Note that this is not permanent, and when you restart your Mac or log out of the user, the default effect is restored. And, after upgrading to OS X Yosemite, this feature was canceled by Apple, only a vague background, does Apple's designer think this is the best effect?