For Titans, the only sets of armor that have both intellect and discipline are only able to be gotten with crucible marks. This forces people into playing PvP, which there are plenty that absolutely despise it (me include, its the worst multiplayer experience ive ever had. Ide rather play a release copy of bf4, no patches, which was horrendous). And there was literally no negative to allowing the exchange. Also, fun is subjective. There is no fun to be had in Destiny's PvP for me. I would infinitely rather run around ina circle, barely paying attention while watching videos, than force myself into PvP and make my day worse off because of it.