Why release an iphone 6 PLUS?

It's really just a bigger version of an iphone 6. I suppose with improved specs such as better battery life and pixels. But it's bugging me why apple did that, it's kinda the same.

Who would buy the iphone 6 plus? Would you say the tech geeks that likes the whole better specs? It boggles me

I think it's to keep up with some of the large screen android devices. The galaxy note 3 for example has a bigger screen (5.7in).