As already mentioned, this only provides additional security while you're inside the house... in which case, it's not exactly necessary, because nobody in their right mind is gonna break into your house if they think you're there. Unless an assassin is after you, that is.
I don't see how this thing prevents the lock from being picked; as far as I can tell, it only stops the door from being pushed open after the lock is opened from the outside... technically that's the same thing, but it's kinda false advertising.

A simple chain or bolt latch would do the exact same job, and is much cheaper.
Now, if you had an electronic deadbolt on the inside of the door which could be locked/unlocked via a remote device on your keychain, that'd be a different story.