Sometimes I need an unzoomed mode because the kanji are too small, that's why. Or there's a detail that is part of the story.
Problem with ACD, one needs to hit two keys, Ctrl+-. I have been sticking with ACD 3.1 because the later versions had become huge monsters, so I don't know if they added customizable keys.
Some scans are too dark so I need a gamma. ACD needs multiple keys to arrive to the gamma - a direct key would have been nice.
And yeah, I mean reading only.
For translation then the zoom becomes mandatory, not just see_all/unzoomed. I also have Notepad open at the same time, moving back and forth from acd to notepad. Well those two, and also the IME Pad and JWPce and Firefox/Babelfish and also a DOS box with Kakasi open [romaji converter that only works under DOS]. It quickly adds to a lot of windows.