What are the advantages of a macro camera?

You could pair this Word up with just about anything else except for "camera" (e.g. macro lens/shot/flash/capable/work/setting/photo etc.) To the best of my knowledge, there is no such thing as a "macro camera". If you're trying to determine what macro images are, this definition hails from the old days of film: it is an image where the ratio of the recorded image size to the actual object size is from 1:1 to 10:1. In other Words, the image recorded on film is the same size as the object (1:1) or is up to 10x larger than the object. If you go beyond 10:1 you have branched into photomicrography. Anything less than 1:1 is "close up" Photography.