The sheer number of answers you've got should tell you that indeed there is something about those macros. But you need to 'get' them yourself to appreciate them

The sheer number of answers you've got should tell you that indeed there is something about those macros. But you need to 'get' them yourself to appreciate them. Each answer exposes one or more facets of macros. Indeed, there is not just 'one' thing that make them worthwhile.