I don't consider those the key effects of Honor; in fact, those are the ones I don't bother with. GGs are very easy to get, so the only thing that SP does is give you one for the first war you fight. Well, the first battle or two of the first war, really, because you'll have one before the war is over. As for the XP, it's nice but there are nicer things out there. For me, the best part about Honor (and this is only true if I'm going for Domination) is the half-price unit upgrades. To get that you also have to take the 10% bonus for a unit in the next tile and the 1 happy point per garrison unit, which are also nice. My first SP choice, every game, is to unlock Tradition. My second, every game except if I'm going for a culture win, is to unlock Liberty. (I don't do that for culture because I don't build enough cities for the 1 culture per city to be worth it.) My third depends on what kind of victory I'm after. Unless I'm going for Domination, I never unlock Honor at all.