Abe, because they fear to being mis-understood. The word "God" is so linked with religion, worship, distinct religion particular worship, that it is not a fitting term for a Deistto use AND be understood.
There is nothing in Nature to indicate that a possible creator wants or needs to be worshipped. Because the care needed to nourish new and old life, we might be tempted to ascribe paternal, maternal qualities to a creator, and be thankful for the care of our nautural parents.
Even the flawed bible agrees that religion is a human invention, with either Cain or Abel holding the patents.
Since the Creationist Creatist names are already taken, let us not use the G word. or C word to avoid confusion, spell it out instead.