I would say that if you're on a tight budget, there are other options. I don't know about others, some people prefer a higher DPI mouse, for me 1800DPI is sufficient for my gaming activities.

I've read online that most people would stick around 1600-1800DPI for average gaming. Not saying that higher DPI is useless, because it is mostly depends on people preference. Even I rarely go over 2000DPI (in my case it was too sensitive, except for when I am using Photoshop). That why most people you see here stick with the DA, Lachesis, and Krait, which in my opinion would suffice.
It's like an analogy of buying a car. I certainly would buy a Ferrari if I had the money.

Don't get me wrong. Mamba is a very good product, I can assure you that. You won't regret that you ever bought it. If it fits you well, then you will really love it.

EDIT: High DPI has variable uses. Some prefer it to be that sensitive, so an extra mile on the mouse is a plus, while others just prefer the casual mouse for gaming

Probably one of the common tactics. They invite friends over to the booth to make it look happening. Something like the cheerleader effect but with booth. 0.0