i can agree with the game being a mindless grind without any challenges, but i cant agree with your second point about pixel rewards being worthless.
nothing in the world entitles you to any grand status, yet in the right circles it can mean a lot. for example you can be top level computer programmer, but no cast director will give a flying fuck about that, while it will help you tremendously when looking for computer related job position. and in-game achievements are the same, nobody outside the game will give a flying fuck about you downing mythic helya, but when looking for a guild or even a pug, the achievement will be highly valuable.