It's not useless but it is not worth the time spent doing it anymore.
On an epic flyer the round trip from Temple of Storms to Dun Niffelem to the Anvil was taking 5+ minutes including the Forging an Alliance quest.
Now that Relics of Ulduar can be turned in for 250 rep you are much better off farming Storm Peaks mobs for drops. I can farm a bunch of mobs to collect 10 relics in around 5 minutes for 250 rep vs. the 5 minutes it would take to gain 75 rep from this exploit.
fyi, Thuderfall is a great place to farm Relics. The re-spawn rates on the giants and dwarf spirits is really great siince it's a daily quest zone. Happy Hunting![]()