The DAC is an amazing multipurpose device!
It's most popular use is allowing you to attach your dumb RGB pixels to your WS281x controller. Simply attach the board on to the controller and program the controller as if the DAC were a single pixel! All of the dumb RGB pixels will behave together as programmed!
The DAC can be used alone or daisy-chained! Just treat each one as a separate pixel.
there are also more advanced uses! The DAC can also be used to drive relays or PWM devices! (eg. servos, fans)