To me, those boxes are all about time. Playing an average of an hour and a half a day, I can probably grind out a life in 2 weeks (21 hours). That is assuming I know what I want for a build and have the gear to do it. Or, for about $110 US, I can get from level 1 to 30 in about an hour. That is saving me 20 hours of grinding. So the question is, is my time (those 20 hours) worth the $110? In my financial state, I believe it is... and that is the key. Yes they are expensive to some people, but to others, they are a value.
Now, if we want to talk real bang for the buck in this game? Those Tensers Weapon Boxes are a HUGE value vs the grind.