Zero serialization. Imagine installing a program and always having it "running". It may be swapped out but littetally everything in it is ready to go when you switch to it's window.
This is a huge PITA with mobile devices - I have no clue what code is, or isn't, being executed at any given time. Even if I force-kill an app, it has still most likely left some background service running, that will still use data, trigger GPS updates, wake the phone up, etc. What I wanted since the very day I first got my smartphone is to have PC-like control over applications.
In a perfect world of total ubiquity of wireless electricity, not to mention infinite CPU speeds and free and unlimited bandwidth, having everything running all the time in some way might be ok. As it is today, we still need the ability to kill software (and have it stay down), up to and including rebooting everything, to deal with obscure bugs in applications, OS and drivers. Not to mention being able to have some semblance of understanding of the device's state.
Except that many apps are so buggy you have to restart them often in practice. NVM won't change that, sadly.