The problem is not metric, but doing transactions in a fraction of a denomination. Its not just the perceived value problem of picking up a coffee for .04BTC. Its also keeping track of the fraction, i.e "whoops, I just paid .011BTC instead of .0011BTC per gram of grapes. It would make much more sence (cents lol) if the gram costs 0.11 GV, and I would not accidentally send 1.10gv. Sorry fraction guys, there is no explanation other than human weakness.