I've just enduring a traumatic experience so forgive me for not downloading a PDF and educating myself for not doing some research before responding.
(Traumatic experience: Drunkioke at the inlaws for a 3rd thursday in November awkward-fest, contact me off-line for juicy details, or rather non juicy details. I lost 9 feedback eliminators to those people).
Let me relay a different item. For example, a light I own, the Chauvet QSpot-150. It's a decent mover, but, the bulb is ON full time. There is a shutter function. it works, but it ain't great. It can do strobing via the shutter that's sort of nifty. For me, it works fine because it's either FULL OPEN shutter or shutter full on. There IS NOT DMX CHANNEL that contols the lamp. Based on how I use this fixture, it's not an issue.
There are multiple reasons for this type of feature. One of which goes with the type of bulb, some bulbs prefer to be on full, while others can take dimming. It's a design thing. Doesn't necessarily mean a cheaper fixture if the bulb stays on full time, but it typically is seen used in that way.
Had I known THEN what I know now, I'd see if I could buy a mover with the same feature set but with dimming.
So, in closing, some fixtures have the option to turn off or dim the bulb, some don't. Download and check your manuals for further clarifications as to what a fixture is capable of doing.