But the general public can see a difference between a smartphone with a 12 key keypad and a device with a qwerty keyboard.

It seems that some of the trademark litigation hinges on confusion.

If Joe public sees an add for the BB Pearl, then walks in a store and tells the clerk: "I saw this phone that could also do email and stuff, it's called Black-something", if the clerk pulls out a BB Pearl, a Blackjack and a Black Pearl, I'm sure Joe Public would immediately look at the BP and reject it. There could be confusion with the other 2.