This is important because it shows that such things can exist. So the common complaint is more about people forgetting that text-based code review tools originally didn't exist and were built. It's just that the visual ones need to be built and/or improved. Perforce makes this easier than git in my opinion because it is more scriptable and has a nice API. Perforce is also built to handle binary files, which is also better than git's design which is built around the assumption that everything is text.
I think there's a lot of nice features to be had in visual programming languages with visual compares. Like I said in another comment, I view text-based programming as a sort of 1.5 dimensional problem, and I think that makes diff tools rather limited. If you change things in a certain way, many diff tools will just say you completely removed a block and then added a new one, when all you did was re-arrange some stuff, and there's actually a lot of shared, unchanged code between the before and after blocks. So it's not like text-based tools don't have issues.