I don't think you can substitute love with points.
Though given how many relationships break up over World of Warcraft, maybe points are better than love. (I don't know how many relationships break up over WoW, but I could imagine it's a few).
Don't think of it as substitution. Think of it as telling the computer (and thus the world). It also provides a log, so the next time you're happy or mad at them, the computer can remind you of a good thing they did.
Though given how many relationships break up over World of Warcraft, maybe points are better than love. (I don't know how many relationships break up over WoW, but I could imagine it's a few).