Wait, isn't it cross play? You could join if you wanted to.
Also, I got both Vita and PS3 versions with mine, thought all copies of the game came with both games. Maybe it's different with physical copoes?
I forgot I could play with PS3 owners.
Boyfriend got the Vita on the awesome Amazon sale for the Assassins Creed: Liberation Edition, and it came with a code for PS All Stars, which does not contain the PS3 version apparently. So I can't play it on the PS3, but I suppose he or I could play it on the Vita for FNF.