Yeah, the only reason I really upgaded was because I had just gotten PS Plus, and it's obvs all digital.
I don't have a problem with digital - in fact I almost prefer it if you have the room to spare, but I don't think it's going to go very far with the new consoles - install files and updates on some of the PS4 games I've played are already in the 30+ gig range *cough*BF4*cough* - couple that with the actual download of the game and there's no telling how huge it would be. That 500gig HDD that came with the PS4 is about the equivalent to an 8 gig Vita memory card - you could probably fit 2 full game downloads on it and the rest would be taken up by saves and OS shit.