Originally Posted by NuSoardGraphite
I wouldn't care that my buddy would have to log on as me. The point being that we want to play together, it's totally ok if he logs on as me, and I log into one of the alternate ID's on my PS4 at home. So in the case of me not giving a rat's ass if I'm logged in as myself or not, doesn't my suggestion work just fine?
Even on the PS3, there are two identifiers - one identifier for the primary account holder (the one that buys the digital content), and a profile(s) for any gamer in the house that uses the content. On the PS3, once an account holder brings in content to play, any profile can access it. The same is true for the PS4.
So with game sharing on the PS4 with your buddy, he uses your account status to make his PS4 your primary machine so that he is able to use his own, separate profile to access your account's content. He is not affecting your cloud saves, trophies, online persona, etc. That all ties into his own profile. He is even unable to buy stuff under your account if you leave the credit card page blank, and likely has to give your password (if you have this optioned turned on like the PS3) to use any funds you haven't spent.
On your PS4 that you must tag as your secondary, you log in as a secondary to play as yourself. You can still buy and use anything you want as yourself. The main restrictions on the secondary machine is that you have to be online so the PSN knows you are you on a secondary machine. Also, Vita remote play is restricted in some unknown way. That's it as far as we know. You and your buddy should have no issues with this setup.