[Spivak]

Which is why nobody really uses furlongs anymore but there are plenty of other units that are still in use. One example I think we're all familiar is the 'Rack Unit' for servers (i.e 1U, 2U) where 1U is 44.45mm. I don't think there would be any additional clarity gained by saying, "I bought a few 88.9mm servers".

[ric2b]

But that's a context specific unit, not intended for general use.

Metric is great for general use simply because of it's multipliers: (...) 1G = 1,000M = 1,000,000K = 1,000,000,000 = 1,000,000,000,000m (...)

And also the simple way many units are related as well, like 1L of water having 1kg of mass (yes, with a certain temperature, pressure, yada yada yada)