I think what you meant to say was "Why NOT?" Haha!
All-in-all, I'm not sure I'd call this thing a BEAST in any sense other than it's ability to hoard that much data. All of the rest of the specs are kinda hovering around others are right now, but for those who find themselves at the end of the line with a 128GB card, if you need more than this thing offers, you might wanna do some re-evaluating.
What I meant by beast was both the huge access to storage both internally and by not just one, but TWO MicroSD card slots (again, TWO???). Also what makes this a beast is by the Harmon Kardon speakers - a definite step in the right direction for ALL Cellphone manufacturers to learn from (co-branding is a great way to enhance value and performance while allowing both manufacturers to leverage each others' successes and reputations and build marketshare).
Still further, I agree with
@jkaod , in regards to the removable battery. Don't get me wrong...I'm not necessarily an advocate of removable batteries per se, since they bring with them added potential contact failure points, and also disrupt the case's integrity to ward off dust, dirt and moisture, however there is a genuine value in being able to easily replace it yourself, as well as manufacturers being able to even add an extended battery option as was the case with the OGD, and (is), with many other phones.
Yet another "benefit" is actually the lower resolution of the screen. I agree with
@cr6 that 1080P (or is it 1080P HD), resolution is plenty for a 5 - 5.5" screen, and will result in less load on the processor/coprocessor as well as less power consumption. Then there's the fingerprint scanner and two huge cameras...
I guess what I'm saying is that in order to be a "beast" IMHO, it doesn't mean that all the specs need to be top end. On the contrary, they should be sufficient at least, to do the job with no lag and have sufficient headroom going forward to last as a serviceable device for at least 2 years. In other words, it should be equipped to do the job, and do it well. Moto X 1st generation is a perfect example of that.
This phone has it all...current top specs in some respects, quite capable specs in others, and even some cutting edge specs where it counts. That's what can set apart a great phone from a "cutting edge" device that trips over itself or is criticized for not hitting on all cylinders.