The SDK is very useful for a smooth login experience if the user has the Facebook app installed, because your app can offer Facebook as a login option, then just pop the user over to the Facebook app, they can tap “okay” (or whatever), and jump back to your app.
That said, we’re going to rip this thing out of our apps ASAP. No framework should be calling network code in “+load”. The convenience for the user (and the dirty tracking Facebook apparently does) is just not worth the trade-off of handing our app’s stability over to Facebook.