Ok, so a bit more clarity has been released regarding the details of the feature:http://www.gamespot....6/1100-6421730/
That article is a couple days old, but it hadn't been mentioned yet, so I thought I would share it.
So basically, you can allow a friend to play an entire game that you own, but you have re authorize that game every hour and of course you cannot use the ps4 for anything else while this is happening. I would say that one hour 'check-in' is a good way to try and limit too much abuse of the system, a sort of drm-lite. Its too bad you can't do anything else with the ps4 during this though, but again, I see that as a way to limit abuse.
The whole point of the program is a glorified demo system. Sony won't force developers to provide demos, so instead they created a system mechanism that allows anyone that owns a game to demo it out to anyone else.
One thing that is not clear is how saves work. On the original Kotaku story listed in this thread, there was an update to the article that stated that since the remote user is basically taking over your local ps4, any game saves are tied to your account, not to that remote user. Then, the more recent article above states that saves are in fact tied to the remote users account. I wonder which it is.