1/3 can easily be measured in metric... it's just not a whole number.
Far out I can invent a system that is unique to everything, and I can create my own abominable conversion ratios all I like. It doesn't make the system superior, it makes my system necessarily inferior.
My TV is now 12 Settos in size. My surround system consumes 12 audots of power. My fridge holds 12 cubic fudo of room.
There. Now everything is easily divisible by 12ths.
I won't even go into conversion factors on this insanity.
Metric is objectively the better system to anyone that doesn't have a decades-long familiarity with the stupidity that is the imperial system. That's coming from an american without a college education, by the way. I am the target demographic for the pro-imperial people. I wasn't abducted into any metric-only education system and forced to convert or fail and disappoint my family. I was a disappointment by my own hand, thank you very much.