Yeah, having metric everything makes it easy to do conversions and correlating with different properties of matter, you're using the language of science (and most of the world), with proper definitions in terms of reality: atoms (for kg), distance in terms of c*some_time, volume related to mass (1ml of water => 1g of water, you can get very precise with temperature as an input). Having a standard for orders of magnitude that's consistent (micro, milli, kilo, mega, giga) is just the cherry on top.