PS4 doesn't auto-install disc games, it just caches them.

[CrankyStorming]

Article on Gamepur [http://www.gamepur.com/news/12566-new-ps4-details-automatic-caching-games-not-install-voice-commands-without-.html]

Shuhei Yoshida via his personal Twitter account has revealed never heard before details about Playstation 4.

Yoshida first confirmed that Playstation 4 does automaic cashing to games, and its not the mandatory install. This is really huge news for Playstation 4, it basically mean, if you want to play CoD Ghosts and Killzone, you won't need 100GB of space (50GB each,) you'll just need 50GB to cache them. That's so cool!

What this basically means is that full game dumping from the BD is just temporary, so you'll only need to upgrade the hard disk if you plan on going all-download. What we don't know is whether permanent installs are out of the question.

 

[Fireaxe]

This actually sounds like a sneaky way to implement always online as a "feature" to me.. it's not like disk space is a valuable commodity these days.