Continuous mode is when you select burst mode instead of single shot, or a custom mode, where you select initial delay (0-10 secs) and number of shots (1-10).
So for example you can set 1 second and 3 frames, set the Av/Tv EV to 2EV, and Bracketing mode +/-
When you press the shutter ONCE, you get three shots at 0, -2 and +2 EV respectively. Or you can do it manually.
The advantage is that you don't use any script this way, only software capabilities (original+chdk).