The connector (resp Port) was too chunky for laptops and you didnt get sound over dvi, but other than that it worked just Fine each and every time. Never had issues upgrading stuff from VGA to DVI in an industrial Environment back then.
https://en.wikipedia.org/wiki/Mini-DVI
Which is cool, but not quite as cool as micro-DVI, which they used for exactly one MacBook Air generation before mini-DisplayPort arrived on the scene
https://en.wikipedia.org/wiki/Micro-DVI
Edit: you are right though. I just pulled up pictures on early G4 variants, and there is indeed full-size DVI. I completely forgot that.
Even DVI had HDCP though, so it too was flawed :-( https://en.wikipedia.org/wiki/High-bandwidth_Digital_Content...