The Germans’ flirtation with strategic bombing died with Walter Wever. Between Udet’s fixation with putting dive brakes on anything and everything, Hitler’s desire for masses of aircraft ASAP, and the reality that the Luftwaffe was going to be, basically, a tactical, ground support air force, the brass decided that the the Norden had no practical apllication for what they were doing.
In addition to the factors you mentioned, I get the idea from the museum plaque above that the Norden was designed for daylight bombing. For their raids on England, didn't the Luftwaffe prefer to operate at night to avoid British fighters?