What does any phone other phone offer thats that much better? Its rumored to have a MircoSD slot so at it at least has expandable storage. What does a Note 5 offer other than a pen? Or the S6 edge other than a curved screen (BB Venice has that as well), or the S6 with a fingerprint scanner? Or a Lg G4 with buttons on the back? You get the drift. Personally in a world of glass slabs, I think a phone that has good specs (which this is rumored to have) and something that makes it really different from everything else will sell well.
A lot of people miss the keyboard on their old BB, and having the option to have that on newer hardware (flagship quality) really hits that nostalgic sweet spot. I can't use a BB10 phone because of app compatibility (Ive tried) but having a high quality hardware keyboard phone along with android lets me do that.