There are pros tho.
For example, have you ever felt sick when you tried to farm Sastasha for lv15 unique gear for Glammering? Or even sick of Brayflox for those three sets of gears?
And you still recieve daily roulette reward so it is efficient if you only run one dungeon per day.
Also, it just purely speeds you up once you reach to level 40.

However currently the cons are too huge that we see more argument rather than supporting on official forum so...