I have to agree with Kizzestra, if you are raiding an endmob with like 1.000.000 HP, 1% is still 10.000 HP, and you can't read between like 23% and 22% when you look on a simple gauge. It just makes things a bit easier, and as a cleric I can heal more accurate when I see the mob hits my MT for like 20% each hit, I can estimate when I cast my CH and it's easier for me than a gauge ... I even wish that I could see it with two decimals for the xp bar in level 59
