The BZB1 is the simplest configuration and has just the main processor board. The configuration is similar to breadboard insertable arduino compatibles such as the Boarduino and ardweeny with out losing the space that an insertable takes up.
When you place an insertable into a breadboard all of the pins that it contacts are "used" up on the breadboard, making them off limits from further use for circuits, even if you don't use those pins in your project. On the BizzyBee none of pins come in contact with breadboard(because they run down the center) until you connect them, so it has the convenience of a lower cost of an insertable without the loss of breadboard space.
It also allows you Processor portability, because you could use several of them for several different projects without having to unwire and pull your arduino out to start a new one.
Just like other insertables the main savings comes from not having the ftdi with each processor, you only need one for several processors to program sketches.
You could use the the BZB2 or BZB3 to program the BZB1, or you would need a separate ftdi breakout board. Also becuse it is a modular system you could just add on the Power/Serial module and it becomes a BZB2, or add the Power/Serial module, the Ctrl IO board and the Outrigger Shield Extender and you would have a BZB3, all of the parts are interchangable and modular, so if you had several you could build which ever configuration you needed for your current project and reconfigure if your next projects had different needs.
The most common usage is to get a BZB3 as a master unit and several BZB1s to use as standalone project boards, this configuration is available in both our Maker pack and Dev pack reward levels.
Thanks for the interest.
BOZ